Run CPython 2.7 and 3.6 tests with buster image.

.github/workflows/python-package.yml

@@ -2,7 +2,7 @@ name: CI
 
 on:
   push:
-    branches: [main]
+    branches: [main, workflow]
   pull_request:
     branches: [main]
 
@@ -11,13 +11,71 @@ env:
     PIP_NO_PYTHON_VERSION_WARNING: 1
 
 jobs:
+  build-27-buster:
+    # https://github.com/actions/setup-python/issues/672#issuecomment-1589120020
+    runs-on: ubuntu-latest
+    container:
+      image: python:2.7.18-buster
+
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ["2.7"]
+
+    steps:
+      - name: Cancel previous runs
+        uses: styfle/[email protected]
+        with:
+          all_but_latest: true
+
+      - name: Check out project
+        uses: actions/checkout@v3
+
+      - name: Install dependencies
+        run: python -m pip install -e .
+
+      - name: List installed packages
+        run: python -m pip list
+
+      - name: Run tests
+        run: python -m unittest discover
+
+  build-36-buster:
+    # https://github.com/actions/setup-python/issues/672#issuecomment-1589120020
+    runs-on: ubuntu-latest
+    container:
+      image: python:3.6.15-buster
+
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ["3.6"]
+
+    steps:
+      - name: Cancel previous runs
+        uses: styfle/[email protected]
+        with:
+          all_but_latest: true
+
+      - name: Check out project
+        uses: actions/checkout@v3
+
+      - name: Install dependencies
+        run: python -m pip install -e .
+
+      - name: List installed packages
+        run: python -m pip list
+
+      - name: Run tests
+        run: python -m unittest discover
+
   build:
     runs-on: ubuntu-latest
 
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["2.7", "3.6", "3.7", "3.8", "3.9", "3.10", "3.11", pypy-2.7, pypy-3.9]
+        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12.0-rc.1", pypy-2.7, pypy-3.10]
 
     steps:
       - name: Cancel previous runs
@@ -38,6 +96,8 @@ jobs:
         run: |
           echo "dir=$(python -m pip cache dir)" >> $GITHUB_OUTPUT
           echo "py=$(python -c'import sys; print("%d.%d" % sys.version_info[:2])')" >> $GITHUB_OUTPUT
+          echo "dir=$(python -m pip cache dir)"
+          echo "py=$(python -c'import sys; print("%d.%d" % sys.version_info[:2])')"
 
       - name: Cache pip
         uses: actions/cache@v3