Add GitHub Action to update Markdown file dates

Author: brown9804

.github/workflows/update-md-date.yml

@@ -0,0 +1,58 @@
+name: Update Last Modified Date
+
+on:
+  pull_request:
+    branches:
+      - main
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  update-date:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          ref: ${{ github.head_ref || github.ref_name }}
+
+      - name: Set up Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: '3.x'
+
+      - name: Install dependencies
+        run: pip install python-dateutil
+
+      - name: Configure Git 
+        run: |
+          git config --global user.email "github-actions[bot]@users.noreply.github.com"
+          git config --global user.name "github-actions[bot]"
+
+      - name: Update last modified date in Markdown files
+        run: python .github/workflows/update_date.py
+
+      - name: Commit and merge changes
+        env:
+          PR_BRANCH: ${{ github.head_ref || github.ref_name }}
+          GIT_AUTHOR_NAME: github-actions[bot]
+          GIT_AUTHOR_EMAIL: github-actions[bot]@users.noreply.github.com
+          GIT_COMMITTER_NAME: github-actions[bot]
+          GIT_COMMITTER_EMAIL: github-actions[bot]@users.noreply.github.com
+        run: |
+          # Ensure we're on the correct branch
+          git switch -c "$PR_BRANCH" || git switch "$PR_BRANCH"
+          
+          # Stage and commit all changes (new, modified, deleted)
+          git add -A
+          git diff --staged --quiet || git commit -m "Update last modified date in Markdown files"
+          
+          # Pull and merge existing changes from remote
+          git pull origin "$PR_BRANCH" --no-rebase
+          
+          # Push all changes to the PR branch
+          git push origin "$PR_BRANCH"