Introduce reusable workflow to update pre-commit dependenices

.github/workflows/automated-changenote.yml

@@ -0,0 +1,77 @@
+name: Automated Change Note
+
+on:
+  workflow_call:
+
+permissions:
+  pull-requests: write
+
+env:
+  COMMIT_MESSAGE: "Add changenote."
+
+jobs:
+  changenote:
+    name: Automated Change Note
+    if: github.repository != 'beeware/.github'
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    steps:
+
+      - name: Checkout
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 1
+          token: ${{ secrets.BRUTUS_PAT_TOKEN }}
+
+      - name: Configure git
+        run: |
+          git config user.email "brutus@beeware.org"
+          git config user.name "Brutus (robot)"
+
+      - name: Change Note Details
+        id: changenote
+        run: |
+          # If the last commit was a changenote commit, then a changenote commit is not needed on this run
+          if [[ "${{ github.event.head_commit.message }}" == "${COMMIT_MESSAGE}"* ]]; then
+            echo "needed=false" >> ${GITHUB_OUTPUT}
+          else
+            echo "needed=true" >> ${GITHUB_OUTPUT}
+            
+            API_URL="${{ github.api_url }}/repos/${{ github.repository }}/commits/${{ github.event.head_commit.id }}/pulls"
+            PR_NUM=$(curl -s -H "Accept: application/vnd.github+json" "${API_URL}" | jq -r '.[].number')
+            echo "filename="./changes/${PR_NUM}.misc.rst"" >> ${GITHUB_OUTPUT}
+          fi
+
+      - name: Create Dependabot Change Note
+        id: dependabot
+        if: startsWith(github.ref, 'refs/heads/dependabot/') && (steps.changenote.outputs.needed == 'true')
+        run: |
+          # Create change note from first line of dependabot commit
+          NEWS=$(printf "%s" "${{ github.event.head_commit.message }}" | head -n1 | sed -e 's/Bump/Updated/')
+          printf "%s.\n" "${NEWS}" > "${{ steps.changenote.outputs.filename }}"
+
+          git add "${{ steps.changenote.outputs.filename }}"
+          echo "skip=true" >> ${GITHUB_OUTPUT}
+
+      - name: Create pre-commit Autoupdate Change Note
+        if: github.ref == 'refs/heads/pre-commit-autoupdate' && (steps.changenote.outputs.needed == 'true')
+        run: |
+          printf 'Updated hooks for ``pre-commit`` to the latest version.\n' > "${{ steps.changenote.outputs.filename }}"
+
+          git add "${{ steps.changenote.outputs.filename }}"
+
+      - name: Commit and Push changenote
+        if: steps.changenote.outputs.needed == 'true'
+        run: |
+          if [[ "${{ steps.dependabot.outputs.skip }}" == "true" ]]; then
+            # "dependabot skip" tells Dependabot to continue rebasing this branch despite foreign commits
+            COMMIT_MESSAGE="${COMMIT_MESSAGE} [dependabot skip]"
+          fi
+          
+          # If there's anything staged, push it; if the changenote already
+          # exists from a previous run of this workflow, nothing to push.
+          if [[ $(git status --porcelain) ]]; then
+            echo "Pushing commit..."
+            git commit -m "${COMMIT_MESSAGE}"
+            git push origin
+          fi

.github/workflows/pre-commit-update.yml

@@ -0,0 +1,60 @@
+name: Update pre-commit
+
+on:
+  workflow_call:
+    inputs:
+      pre-commit-source:
+        description: "The arguments for `pip install` to install pre-commit; use ./path/to/package[dev] for the repo's pinned version."
+        default: '.[dev]'
+        type: string
+
+permissions:
+  pull-requests: write
+
+jobs:
+  pre-commit-update:
+    name: Update pre-commit
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    steps:
+
+      - name: Checkout
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 1
+          token: ${{ secrets.BRUTUS_PAT_TOKEN }}
+
+      - name: Configure git
+        run: |
+          git config user.email "brutus@beeware.org"
+          git config user.name "Brutus (robot)"
+
+      - name: Set up Python
+        uses: actions/setup-python@v4.5.0
+        with:
+          python-version: "3.X"
+
+      - name: Install pre-commit
+        run: python -m pip install ${{ inputs.pre-commit-source }}
+
+      - name: Update pre-commit hooks
+        run: |
+          pre-commit autoupdate
+          pre-commit install-hooks
+
+      - name: Run pre-commit
+        # pre-commit returns non-zero when files are changed
+        continue-on-error: true
+        run: pre-commit run --all-files
+
+      - name: Create Pull Request
+        uses: peter-evans/create-pull-request@v4.2.3
+        with:
+          token: ${{ secrets.BRUTUS_PAT_TOKEN }}
+          branch: pre-commit-autoupdate
+          title: Update pre-commit hooks
+          commit-message: Auto-update pre-commit hooks
+          body: |
+            Update versions of tools in pre-commit configs to latest version
+            and run updated hook over repo.
+          labels: dependencies