docs: update README for v1.2.1 (#233)

- Updated v1.2.1 installation guide.
- Formatted README to pass
[super-linter](https://github.com/super-linter/super-linter)

---------

Signed-off-by: Junjie Gao <junjiegao@microsoft.com>

Author: JeyJeyGao

README.md

@@ -9,6 +9,7 @@ The `notation-azure-kv` plugin allows you to sign the Notation-generated payload
 The plugin supports several [credential types](./docs/plugin-config.md#credential_type).
 
 ## Installation the AKV plugin
+
 Before you begin, make sure the latest version of the [Notation CLI has been installed](https://notaryproject.dev/docs/installation/cli/).
 
 1. Navigate to the [Releases](https://github.com/Azure/notation-azure-kv/releases) page and choose a release of `notation-azure-kv`.
@@ -19,35 +20,41 @@ Before you begin, make sure the latest version of the [Notation CLI has been ins
    For Notation >= v1.1.0, please use [notation plugin install](https://github.com/notaryproject/notation/blob/v1.1.0/specs/commandline/plugin.md#notation-plugin-install) command to automatically install azure-kv plugin.
 
    For Linux amd64:
+
    ```
-   notation plugin install --url https://github.com/Azure/notation-azure-kv/releases/download/v1.2.0/notation-azure-kv_1.2.0_linux_amd64.tar.gz --sha256sum 06bb5198af31ce11b08c4557ae4c2cbfb09878dfa6b637b7407ebc2d57b87b34 
+   notation plugin install --url https://github.com/Azure/notation-azure-kv/releases/download/v1.2.1/notation-azure-kv_1.2.1_linux_amd64.tar.gz --sha256sum 67c5ccaaf28dd44d2b6572684d84e344a02c2258af1d65ead3910b3156d3eaf5
    ```
 
    For Linux arm64:
+
    ```
-   notation plugin install --url https://github.com/Azure/notation-azure-kv/releases/download/v1.2.0/notation-azure-kv_1.2.0_linux_arm64.tar.gz --sha256sum 49520105bdb707a7bd3a519c55cc1541fbb336ab45b665c9cb2f84593f20ff29
+   notation plugin install --url https://github.com/Azure/notation-azure-kv/releases/download/v1.2.1/notation-azure-kv_1.2.1_linux_arm64.tar.gz --sha256sum 77bbdfb785e22f8b1cae46392200a453a428009c4450a8dc86e10551cc06f28e
    ```
 
    For Windows amd64:
+
    ```
-   notation plugin install --url https://github.com/Azure/notation-azure-kv/releases/download/v1.2.0/notation-azure-kv_1.2.0_windows_amd64.zip --sha256sum 4478b4a323363e264924349bf7007d4201621024b0f9252e0cfde42c0938c667
+   notation plugin install --url https://github.com/Azure/notation-azure-kv/releases/download/v1.2.1/notation-azure-kv_1.2.1_windows_amd64.zip --sha256sum 416eb490a83e8371407cbff1abe0588c84b8cdd34372f936cb1f913b7d0da8c1
    ```
 
    For macOS amd64:
+
    ```
-   notation plugin install --url https://github.com/Azure/notation-azure-kv/releases/download/v1.2.0/notation-azure-kv_1.2.0_darwin_amd64.tar.gz --sha256sum 4b5a3480fc1d6844a69f7d9483530e9be24a74441fd571ccd5eec9f6a5337eed
+   notation plugin install --url https://github.com/Azure/notation-azure-kv/releases/download/v1.2.1/notation-azure-kv_1.2.1_darwin_amd64.tar.gz --sha256sum 4c360d362a9448b46f98046257d5b270b2c5b1beb04c14263e59cead898902c9
    ```
 
    For macOS arm64:
+
    ```
-   notation plugin install --url https://github.com/Azure/notation-azure-kv/releases/download/v1.2.0/notation-azure-kv_1.2.0_darwin_arm64.tar.gz --sha256sum 2bcfc0ee3ad1cbb1854110e3f02b89d46c14feb5736de37cd237b9668f378f2f
+   notation plugin install --url https://github.com/Azure/notation-azure-kv/releases/download/v1.2.1/notation-azure-kv_1.2.1_darwin_arm64.tar.gz --sha256sum bf6e07fdf309c194c99870c8a2a326fa14f9f7572fcf61948d1fcb3249ab3285
    ```
 
    **Manually install**:
 
    For Linux Bash:
+
    ```bash
-   version=1.2.0
+   version=1.2.1
    arch=amd64
    install_path="${HOME}/.config/notation/plugins/azure-kv"
 
@@ -66,8 +73,9 @@ Before you begin, make sure the latest version of the [Notation CLI has been ins
    ```
 
    For macOS Zsh:
+
    ```zsh
-   version=1.2.0
+   version=1.2.1
    arch=arm64
    install_path="${HOME}/Library/Application Support/notation/plugins/azure-kv"
 
@@ -86,8 +94,9 @@ Before you begin, make sure the latest version of the [Notation CLI has been ins
    ```
 
    For Windows Powershell:
+
    ```powershell
-   $version = "1.2.0"
+   $version = "1.2.1"
    $arch = "amd64"
    $install_path = "${env:AppData}\notation\plugins\azure-kv"
 
@@ -107,16 +116,18 @@ Before you begin, make sure the latest version of the [Notation CLI has been ins
    mkdir ${install_path}
    Expand-Archive -Path ${zip_file} -DestinationPath ${install_path}
    ```
+
 3. Run `notation plugin list` and confirm the `azure-kv` plugin is installed.
 
 ## Getting started
+
 1. [Sign and verify an artifact with a self-signed Azure Key Vault certificate](docs/self-signed-workflow.md)
 2. [Sign and verify an artifact with a certificate signed by a trusted CA in Azure Key Vault](docs/ca-signed-workflow.md)
 3. [Plugin configuration](docs/plugin-config.md)
 
 ## Contributing
 
-This project welcomes contributions and suggestions.  Most contributions require you to agree to a
+This project welcomes contributions and suggestions. Most contributions require you to agree to a
 Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us
 the rights to use your contribution. For details, visit <https://cla.opensource.microsoft.com>.