Tweak CI config

.github/workflows/ci.yml

@@ -6,6 +6,10 @@ on:
   pull_request:
     branches: [main]
 
+concurrency:
+  group: ${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   lint:
     runs-on: ubuntu-latest
@@ -45,10 +49,6 @@ jobs:
       with:
         python-version: ${{ matrix.python-version }}
 
-    - name: Install dependencies
-      run: |
-        python -m pip install --upgrade pip setuptools wheel
-        python -m pip install --upgrade tox tox-py tox-venv
     - name: Start dummy client
       uses: Eun/http-server-action@v1
       with:
@@ -62,7 +62,12 @@ jobs:
             "json": "application/json",
             "txt": "text/plain"
           }
-    - run: curl -vvvv http://localhost:8020/index.html
+
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip setuptools wheel
+        python -m pip install --upgrade tox tox-py
+
     - name: Run tox targets for Python ${{ matrix.python-version }}
       if: ${{ matrix.toxenv != 'wagtailmain' }}
       continue-on-error: ${{ matrix.experimental }}

tox.ini

@@ -1,11 +1,15 @@
 [tox]
+usedevelop = true
+requires = tox >= 3.23.0, < 4.0
+           tox-py >= 1.1.0
+
+# note: use py and non-dotted python version as we use tox-py
 envlist =
-    python{3.8,3.9,3.10}-django{2.2}-wagtail{2.13}
-    python{3.8,3.9,3.10}-django{3.2}-wagtail{2.15,2.16}
-    python{3.10}-django{4.0}-wagtail{2.16,main}
+    py{38,39,310}-django{2.2}-wagtail{2.13}
+    py{38,39,310}-django{3.2}-wagtail{2.15,2.16}
+    py{310}-django{4.0}-wagtail{2.16,main}
 
 [testenv]
-usedevelop = true
 setenv =
     PYTHONPATH = {toxinidir}
     DJANGO_SETTINGS_MODULE = wagtail_headless_preview.tests.settings