add git hook notice (#8436)

.github/template/git-hooks-note.md

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+The git hooks are available for **azure-cli** and **azure-cli-extensions** repos. They could help you run required checks before creating the PR. 
+
+Please sync the latest code with latest dev branch (for **azure-cli**) or main branch (for **azure-cli-extensions**). 
+After that please run the following commands to enable git hooks:
+
+```bash
+pip install azdev --upgrade
+azdev setup -c <your azure-cli repo path> -r <your azure-cli-extensions repo path>
+
+```

.github/workflows/GitHookNotice.yml

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+name: Git Hook Notice
+on:
+  pull_request_target:
+    types: [opened]
+    branches:
+      - main
+
+permissions: {}
+
+jobs:
+  git-hook-notice:
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+    name: Introduce git hook in developer env
+    steps:
+      - name: Checkout git hook notice message
+        uses: actions/checkout@v4
+        with:
+          sparse-checkout: |
+            .github/template/git-hooks-note.md
+      - name: Comment on pull request
+        uses: mshick/add-pr-comment@v2
+        with:
+           repo-token: ${{ secrets.GITHUB_TOKEN }}
+           message-id: gitHookNoticeComment
+           message-path: |
+            .github/template/git-hooks-note.md