Change references of pennylane master to main (#1351)

**Context:**
Pennylane changed its default branch from master to main. [Some of the
workflows](https://github.com/PennyLaneAI/pennylane-lightning/actions/runs/22735447893/job/65935488882#step:10:16)
in lightning have started to fail with their pennylane@master
references.

**Description of the Change:**
Change all references of pennylane master to main.

**Benefits:**
Workflows and reference to pennylane will be updated.

**Possible Drawbacks:**
None

**Related GitHub Issues:**
N/A

---------

Co-authored-by: ringo-but-quantum <github-ringo-but-quantum@xanadu.ai>

Author: runora95

.github/CHANGELOG.md

@@ -128,6 +128,9 @@ Jake Zaia.
 
 <h3>Internal changes ⚙️</h3>
 
+- Updated references to Pennylane's `master` to reference `main`.
+  [(#1351)](https://github.com/PennyLaneAI/pennylane-lightning/pull/1351)
+
 - Pinned NumPy to versions preceding 2.4 on CIs as `pyscf` is not compatible with the new version of NumPy yet.
   [(#1315)](https://github.com/PennyLaneAI/pennylane-lightning/pull/1315)
 

.github/CONTRIBUTING.md

@@ -3,7 +3,7 @@
 Thank you for taking the time to contribute to PennyLane-Lightning!
 :confetti_ball: :tada: :fireworks: :balloon:
 
-For details on how to contribute, please see the [PennyLane contribution guide](https://github.com/PennyLaneAI/pennylane/blob/master/.github/CONTRIBUTING.md).
+For details on how to contribute, please see the [PennyLane contribution guide](https://github.com/PennyLaneAI/pennylane/blob/main/.github/CONTRIBUTING.md).
 
 
 \- The PennyLane team

.github/workflows/compat-docker-latest.yml

@@ -15,6 +15,6 @@ jobs:
     uses: ./.github/workflows/docker_linux_x86_64.yml
     with:
       lightning-version: master
-      pennylane-version: master
+      pennylane-version: main
       push-to-dockerhub: false
     secrets: inherit # pass all secrets

.github/workflows/docker_linux_x86_64.yml

@@ -14,7 +14,7 @@ on:
       pennylane-version:
         type: string
         required: false
-        default: master
+        default: main
         description: The version of PennyLane to use. This should be a valid git tag, e.g. v0.36.0.
       push-to-dockerhub:
         type: boolean
@@ -29,7 +29,7 @@ on:
       pennylane-version:
         type: string
         required: false
-        default: master
+        default: main
         description: The version of PennyLane to use. This should be a valid git tag, e.g. v0.36.0.
       push-to-dockerhub:
         type: boolean

.github/workflows/tests_gpu_python.yml

@@ -184,7 +184,7 @@ jobs:
         if: inputs.pennylane-version == 'latest'
         run: |
           cd pennylane
-          git checkout master
+          git checkout main
           python -m pip uninstall -y pennylane && python -m pip install . -vv --no-deps
 
       - name: Switch to release build of PennyLane

.github/workflows/tests_lgpumpi_python.yml

@@ -157,7 +157,7 @@ jobs:
         if: inputs.pennylane-version == 'latest'
         run: |
           cd pennylane
-          git checkout master
+          git checkout main
           python -m pip uninstall -y pennylane && python -m pip install . -vv --no-deps
 
       - name: Switch to release build of PennyLane

.github/workflows/tests_lkcpu_python.yml

@@ -258,7 +258,7 @@ jobs:
         if: inputs.pennylane-version == 'latest'
         run: |
           cd pennylane
-          git checkout master
+          git checkout main
           python -m pip uninstall -y pennylane && python -m pip install . -vv --no-deps
 
       - name: Switch to release build of PennyLane

.github/workflows/tests_lkcuda_python.yml

@@ -233,7 +233,7 @@ jobs:
         if: inputs.pennylane-version == 'latest'
         run: |
           cd pennylane
-          git checkout master
+          git checkout main
           python -m pip uninstall -y pennylane && python -m pip install . -vv --no-deps
 
       - name: Switch to release build of PennyLane

.github/workflows/tests_lkmpi_cuda_python.yml

@@ -185,7 +185,7 @@ jobs:
         if: inputs.pennylane-version == 'latest'
         run: |
           cd pennylane
-          git checkout master
+          git checkout main
           python -m pip uninstall -y pennylane && python -m pip install . -vv --no-deps
 
       - name: Switch to release build of PennyLane

.github/workflows/tests_lqcpu_python.yml

@@ -196,7 +196,7 @@ jobs:
         if: inputs.pennylane-version == 'latest'
         run: |
           cd pennylane
-          git checkout master
+          git checkout main
           python -m pip uninstall -y pennylane && python -m pip install . -vv --no-deps
 
       - name: Switch to release build of PennyLane