Adopt GHA dynamic-matrix

.github/workflows/tox.yml

@@ -10,58 +10,52 @@ on:
       - main
 
 jobs:
+  pre:
+    name: pre
+    runs-on: ubuntu-22.04
+    outputs:
+      matrix: ${{ steps.generate_matrix.outputs.matrix }}
+    steps:
+      - name: Determine matrix
+        id: generate_matrix
+        uses: coactions/matrix@main
+        with:
+          other_names: |
+            lint
+            packaging
+            docs
   build:
     name: ${{ matrix.name }}
-    runs-on: ${{ matrix.os || 'ubuntu-latest' }}
+    needs: pre
+    runs-on: ${{ matrix.os || 'ubuntu-22.04' }}
 
     strategy:
       fail-fast: false
-      matrix:
-        include:
-          - name: docs
-            python: "3.10"
-            tox_env: docs
-          - name: "lint"
-            python: "3.10"
-            tox_env: "lint"
-          - name: "packaging"
-            python: "3.10"
-            tox_env: "packaging"
-
-          - name: py37
-            python: "3.7"
-            tox_env: py37
-          - name: py38
-            python: "3.8"
-            tox_env: py38
-          - name: py39
-            python: "3.9"
-            tox_env: py39
-          - name: py310
-            python: "3.10"
-            tox_env: py310
-          - name: py311
-            python: "~3.11.0-0" # see https://github.com/actions/setup-python/issues/213#issuecomment-1146676713
-            tox_env: py311
+      matrix: ${{ fromJson(needs.pre.outputs.matrix) }}
 
     steps:
       - uses: actions/checkout@v3
-      - name: Set up Python ${{ matrix.python }}
+        with:
+          fetch-depth: 0  # needed by setuptools-scm
+
+      - name: Set up Python ${{ matrix.python_version }}
         uses: actions/setup-python@v4
         with:
-          python-version: ${{ matrix.python }}
+          python-version: ${{ matrix.python_version }}
+
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install tox
-      - name: Test
-        run: "tox -e ${{ matrix.tox_env }}"
+          pip install tox>=4.0
+
+      - name: tox run -e ${{ matrix.passed_name }}
+        run: tox run -e ${{ matrix.passed_name }}
 
   check: # This job does nothing and is only used for the branch protection
     if: always()
     needs:
       - build
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
       - name: Decide whether the needed jobs succeeded or failed
         uses: re-actors/alls-green@release/v1