tools: setup GHA for PR notifier

.github/actions/pr_notifier/pr_notifier.py

@@ -0,0 +1,8 @@
+import sys
+
+from slack_sdk import WebClient
+from slack_sdk.errors import SlackApiError
+
+if __name__ == '__main__':
+    print("Hello world!")
+    print(sys.version)

.github/actions/pr_notifier/requirements.txt

@@ -0,0 +1,8 @@
+#
+# This file is autogenerated by pip-compile
+# To update, run:
+#
+#    pip-compile --generate-hashes tools/dependency/requirements.txt
+#
+slack_sdk==3.5.1 \
+     --hash=sha256:8ceb46f7989d2ba1694dec8555dbda7f750b9216e453da4ad3e32a498bc9ea9a

.github/workflows/pr_notifier.yml

@@ -0,0 +1,24 @@
+on:
+  pull_request:
+  #workflow_dispatch:
+  #schedule:
+  #  - cron: '0 */4 * * *'
+
+jobs:
+  pr_notifier:
+    name: PR Notifier
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Python 3.8
+        uses: actions/setup-python@v2
+        with:
+          python-version: '3.8'
+          architecture: 'x64'
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r ./.github/actions/pr_notifier/requirements.txt
+      - name: Display Python version
+        run: python ./.github/actions/pr_notifier/pr_notifier.py