ci: send regression notifications if prior jobs do not succeed on schedule

.github/maintainers_guide.md

@@ -19,7 +19,7 @@ You can hook `pyenv` into your shell automatically by running `pyenv init` and f
 
 Install necessary Python runtimes for development/testing. It is not necessary
 to install all the various Python versions we test in [continuous integration on
-GitHub Actions](https://github.com/slackapi/python-slack-sdk/blob/main/.github/workflows/ci-build.yml),
+GitHub Actions](https://github.com/slackapi/python-slack-sdk/blob/main/.github/workflows/tests.yml),
 but make sure you are running at least one version that we execute our tests in
 locally so that you can run the tests yourself.
 
@@ -56,7 +56,7 @@ run `source env_3.9.6/bin/activate` again.
 The last step is to install this project's dependencies and run all unit tests; to do so, you can run
 
 ```bash
-$ ./scripts/run_validation.sh 
+$ ./scripts/run_validation.sh
 ```
 
 Also check out [how
@@ -74,7 +74,7 @@ When you make changes to this SDK, please write unit tests verifying if the chan
 Run all the unit tests, code formatter, and code analyzer:
 
 ```bash
-$ ./scripts/run_validation.sh 
+$ ./scripts/run_validation.sh
 ```
 
 Run all the unit tests (no formatter nor code analyzer):

.github/workflows/ci-build.yml → .github/workflows/tests.yml

@@ -1,14 +1,38 @@
 # For more information see: https://help.github.com/actions/language-and-framework-guides/using-python-with-github-actions
-name: CI Build
+name: Test
 
 on:
   push:
     branches:
       - main
   pull_request:
+  schedule:
+    - cron: "0 0 * * *"
+  workflow_dispatch:
 
 jobs:
-  build:
+  typecheck:
+    name: Typechecks
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    strategy:
+      matrix:
+        python-version: ["3.13"]
+    permissions:
+      contents: read
+    steps:
+      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+        with:
+          persist-credentials: false
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@e797f83bcb11b83ae66e0230d6156d7c80228e7c # v6.0.0
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Run mypy verification
+        run: |
+          ./scripts/run_mypy.sh
+  unittest:
+    name: Unit tests
     runs-on: ubuntu-22.04
     timeout-minutes: 15
     strategy:
@@ -68,3 +92,20 @@ jobs:
           token: ${{ secrets.CODECOV_TOKEN }}
           # Run validation generates the coverage file
           files: ./coverage.xml
+  notifications:
+    name: Regression notifications
+    runs-on: ubuntu-latest
+    needs:
+      - typecheck
+      - unittest
+    if: ${{ !success() && github.ref == 'refs/heads/main' && github.event_name != 'workflow_dispatch' }}
+    steps:
+      - name: Send notifications of failing tests
+        uses: slackapi/slack-github-action@91efab103c0de0a537f72a35f6b8cda0ee76bf0a # v2.1.1
+        with:
+          errors: true
+          webhook: ${{ secrets.SLACK_REGRESSION_FAILURES_WEBHOOK_URL }}
+          webhook-type: webhook-trigger
+          payload: |
+            action_url: "${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}"
+            repository: "${{ github.repository }}"

README.md

@@ -1,8 +1,8 @@
 <h1 align="center">Python Slack SDK</h1>
 
 <p align="center">
-    <a href="https://github.com/slackapi/python-slack-sdk/actions/workflows/ci-build.yml">
-        <img alt="CI Build" src="https://img.shields.io/github/actions/workflow/status/slackapi/python-slack-sdk/ci-build.yml"></a>
+    <a href="https://github.com/slackapi/python-slack-sdk/actions/workflows/tests.yml">
+        <img alt="Tests" src="https://img.shields.io/github/actions/workflow/status/slackapi/python-slack-sdk/tests.yml"></a>
     <a href="https://codecov.io/gh/slackapi/python-slack-sdk">
         <img alt="Codecov" src="https://img.shields.io/codecov/c/gh/slackapi/python-slack-sdk"></a>
     <a href="https://pepy.tech/project/slack-sdk">