cicd(github): use ubuntu-20.04

see actions/setup-python#561

.github/workflows/python-package.yml

@@ -11,7 +11,7 @@ on:
 jobs:
 
   test:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     strategy:
       matrix:
         python-version: ["3.6", "3.7", "3.8", "3.9"]
@@ -32,7 +32,7 @@ jobs:
 
   release:
     needs: test
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
     - uses: actions/checkout@v3
     - name: Setup venv
@@ -49,7 +49,8 @@ jobs:
       run: make build
     - name: Publish package
       if: github.event_name == 'release' && github.event.action == 'created'
-      uses: pypa/gh-action-pypi-publish@release/v1
+      # uses: pypa/gh-action-pypi-publish@release/v1
+      uses: pypa/gh-action-pypi-publish@27b31702a0e7fc50959f5ad993c78deac1bdfc29
       with:
         user: __token__
         password: ${{ secrets.PYPI_API_TOKEN }}

.github/workflows/test.yml

@@ -0,0 +1,24 @@
+name: Python package
+
+on: [push]
+
+jobs:
+  build:
+
+    # runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
+    strategy:
+      # You can use PyPy versions in python-version.
+      # For example, pypy-2.7 and pypy-3.8
+      matrix:
+        python-version: ["2.7", "3.7", "3.8", "3.9", "3.10"]
+
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v4
+        with:
+          python-version: ${{ matrix.python-version }}
+      # You can test your matrix by printing the current Python version
+      - name: Display Python version
+        run: python -c "import sys; print(sys.version)"