composite action to update matter_sdk submodule

Author: miduggan24

action.yml

@@ -0,0 +1,67 @@
+name: 'Update matter_sdk submodule'
+description: 'Composite action to update the matter_sdk submodule and create a PR.'
+inputs:
+  target_branch:
+    description: 'Target branch to update the submodule on'
+    required: true
+  app-id:
+    description: 'GitHub App ID'
+    required: true
+  private-key:
+    description: 'GitHub App private key'
+    required: true
+outputs:
+  pr_branch:
+    description: 'The name of the created PR branch (if any)'
+    value: ${{ steps.update_submodule.outputs.pr_branch }}
+runs:
+  using: 'composite'
+  steps:
+    - name: Generate GitHub App token
+      id: generate_token
+      uses: actions/create-github-app-token@v2
+      with:
+        app-id: ${{ inputs.app-id }}
+        private-key: ${{ inputs.private-key }}
+
+    - name: Checkout repository
+      uses: actions/checkout@v6
+      with:
+        ref: ${{ inputs.target_branch }}
+        token: ${{ steps.generate_token.outputs.token }}
+        submodules: false
+
+    - name: Update submodule
+      id: update_submodule
+      shell: bash
+      run: |
+        git submodule update --init third_party/matter_sdk
+        short_hash_before=$(cd third_party/matter_sdk && git rev-parse --short HEAD)
+        echo "short_hash_before=${short_hash_before}" >> $GITHUB_OUTPUT
+        cd third_party/matter_sdk
+        git fetch origin ${{ inputs.target_branch }}
+        git checkout origin/${{ inputs.target_branch }}
+        cd ../..
+        git add third_party/matter_sdk
+        if git diff-index --quiet HEAD; then
+          echo "empty=true" >> $GITHUB_OUTPUT
+          exit 0
+        fi
+        short_hash=$(cd third_party/matter_sdk && git rev-parse --short HEAD)
+        echo "short_hash=${short_hash}" >> $GITHUB_OUTPUT
+        echo "pr_branch=update-matter-sdk-${{ inputs.target_branch }}-${short_hash}" >> $GITHUB_OUTPUT
+
+    - name: Create PR
+      if: steps.update_submodule.outputs.empty != 'true'
+      id: create_pr
+      uses: peter-evans/create-pull-request@v7
+      with:
+        token: ${{ steps.generate_token.outputs.token }}
+        base: ${{ inputs.target_branch }}
+        commit-message: "Update matter_sdk submodule to ${{ steps.update_submodule.outputs.short_hash }}"
+        title: "[${{ inputs.target_branch }}] Update matter_sdk submodule to ${{ steps.update_submodule.outputs.short_hash }}"
+        body: |
+          Bumps matter_sdk submodule from `${{ steps.update_submodule.outputs.short_hash_before }}` to `${{ steps.update_submodule.outputs.short_hash }}`.
+
+          See diff at https://github.com/SiliconLabsSoftware/matter_sdk/compare/${{ steps.update_submodule.outputs.short_hash_before }}...${{ steps.update_submodule.outputs.short_hash }}
+        branch: ${{ steps.update_submodule.outputs.pr_branch }}