[Release 0.7] Update all docs to reflect the new branch 'release/0.7' (#12187)

### Summary
[PLEASE REMOVE] See [CONTRIBUTING.md's Pull
Requests](https://github.com/pytorch/executorch/blob/main/CONTRIBUTING.md#pull-requests)
for ExecuTorch PR guidelines.

[PLEASE REMOVE] If this PR closes an issue, please add a `Fixes
#<issue-id>` line.

[PLEASE REMOVE] If this PR introduces a fix or feature that should be
the upcoming release notes, please add a "Release notes: <area>" label.
For a list of available release notes labels, check out
[CONTRIBUTING.md's Pull
Requests](https://github.com/pytorch/executorch/blob/main/CONTRIBUTING.md#pull-requests).

### Test plan
[PLEASE REMOVE] How did you test this PR? Please write down any manual
commands you used and note down tests that you have written if
applicable.

Author: psiddh

docs/README.md

@@ -40,7 +40,7 @@ To build the documentation locally:
 1. Clone the ExecuTorch repo to your machine.
 
    ```bash
-   git clone -b viable/strict https://github.com/pytorch/executorch.git && cd executorch
+   git clone -b release/0.7 https://github.com/pytorch/executorch.git && cd executorch
    ```
 
 1. If you don't have it already, start either a Python virtual envitonment:

docs/source/getting-started.md

@@ -168,7 +168,7 @@ ExecuTorch provides C++ APIs, which can be used to target embedded or mobile dev
 CMake is the preferred build system for the ExecuTorch C++ runtime. To use with CMake, clone the ExecuTorch repository as a subdirectory of your project, and use CMake's `add_subdirectory("executorch")` to include the dependency. The `executorch` target, as well as kernel and backend targets will be made available to link against. The runtime can also be built standalone to support diverse toolchains. See [Using ExecuTorch with C++](using-executorch-cpp.md) for a detailed description of build integration, targets, and cross compilation.
 
 ```
-git clone -b viable/strict https://github.com/pytorch/executorch.git
+git clone -b release/0.7 https://github.com/pytorch/executorch.git
 ```
 ```python
 # CMakeLists.txt

docs/source/llm/getting-started.md

@@ -45,7 +45,7 @@ cd et-nanogpt
 
 # Clone the ExecuTorch repository.
 mkdir third-party
-git clone -b viable/strict https://github.com/pytorch/executorch.git third-party/executorch && cd third-party/executorch
+git clone -b release/0.7 https://github.com/pytorch/executorch.git third-party/executorch && cd third-party/executorch
 
 # Create either a Python virtual environment:
 python3 -m venv .venv && source .venv/bin/activate && pip install --upgrade pip
@@ -79,7 +79,7 @@ pyenv virtualenv 3.10 executorch
 pyenv activate executorch
 
 # Clone the ExecuTorch repository.
-git clone -b viable/strict https://github.com/pytorch/executorch.git third-party/executorch && cd third-party/executorch
+git clone -b release/0.7 https://github.com/pytorch/executorch.git third-party/executorch && cd third-party/executorch
 
 # Install requirements.
 PYTHON_EXECUTABLE=python ./install_executorch.sh

docs/source/using-executorch-building-from-source.md

@@ -42,7 +42,7 @@ portability details.
 
    ```bash
    # Clone the ExecuTorch repo from GitHub
-   git clone -b viable/strict https://github.com/pytorch/executorch.git && cd executorch
+   git clone -b release/0.7 https://github.com/pytorch/executorch.git && cd executorch
    ```
 
 ### Create a Virtual Environment

docs/source/using-executorch-ios.md

@@ -96,7 +96,7 @@ xcode-select --install
 2. Clone ExecuTorch:
 
 ```bash
-git clone -b viable/strict https://github.com/pytorch/executorch.git --depth 1 --recurse-submodules --shallow-submodules && cd executorch
+git clone -b release/0.7 https://github.com/pytorch/executorch.git --depth 1 --recurse-submodules --shallow-submodules && cd executorch
 ```
 
 3. Set up [Python](https://www.python.org/downloads/macos/) 3.10+ and activate a virtual environment:

examples/demo-apps/android/LlamaDemo/docs/delegates/mediatek_README.md

@@ -24,7 +24,7 @@ In this section, we will need to set up the ExecuTorch repo first with Conda env
 Checkout ExecuTorch repo and sync submodules
 
 ```
-git clone -b viable/strict https://github.com/pytorch/executorch.git && cd executorch
+git clone -b release/0.7 https://github.com/pytorch/executorch.git && cd executorch
 ```
 
 Create either a Python virtual environment:

examples/demo-apps/android/LlamaDemo/docs/delegates/qualcomm_README.md

@@ -22,7 +22,7 @@ In this section, we will need to set up the ExecuTorch repo first with Conda env
 Checkout ExecuTorch repo and sync submodules
 
 ```
-git clone -b viable/strict https://github.com/pytorch/executorch.git && cd executorch
+git clone -b release/0.7 https://github.com/pytorch/executorch.git && cd executorch
 ```
 
 Create either a Python virtual environment:
@@ -238,4 +238,4 @@ If the app successfully run on your device, you should see something like below:
 </p>
 
 ## Reporting Issues
-If you encountered any bugs or issues following this tutorial please file a bug/issue here on Github.
+If you encountered any bugs or issues following this tutorial please file a bug/issue here on Github.

examples/demo-apps/android/LlamaDemo/docs/delegates/xnnpack_README.md

@@ -24,7 +24,7 @@ In this section, we will need to set up the ExecuTorch repo first with Conda env
 Checkout ExecuTorch repo and sync submodules
 
 ```
-git clone -b viable/strict https://github.com/pytorch/executorch.git && cd executorch
+git clone -b release/0.7 https://github.com/pytorch/executorch.git && cd executorch
 ```
 
 Create either a Python virtual environment:

examples/demo-apps/apple_ios/LLaMA/docs/delegates/mps_README.md

@@ -17,7 +17,7 @@ In this section, we will need to set up the ExecuTorch repo first with Conda env
 Checkout ExecuTorch repo and sync submodules
 
 ```
-git clone -b viable/strict https://github.com/pytorch/executorch.git && cd executorch
+git clone -b release/0.7 https://github.com/pytorch/executorch.git && cd executorch
 ```
 
 Create either a Python virtual environment:

examples/demo-apps/apple_ios/LLaMA/docs/delegates/xnnpack_README.md

@@ -16,7 +16,7 @@ In this section, we will need to set up the ExecuTorch repo first with Conda env
 Checkout ExecuTorch repo and sync submodules
 
 ```
-git clone -b viable/strict https://github.com/pytorch/executorch.git && cd executorch
+git clone -b release/0.7 https://github.com/pytorch/executorch.git && cd executorch
 ```
 
 Create either a Python virtual environment: