add matrix so github doesn't get confused

.github/workflows/docs.yaml

@@ -22,6 +22,11 @@ jobs:
   accessibility:
     if: contains(toJson(github.event.commits), '[ci skip]') == false
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: true
+      matrix:
+        python-version: [ 3.9 ]
+        os: [ ubuntu-latest ]
 
     steps:
     - uses: actions/checkout@v2
@@ -29,7 +34,7 @@ jobs:
     - name: Set up Python
       uses: actions/setup-python@v2
       with:
-        python-version: 3.9
+        python-version: ${{ matrix.python-version }}
 
     - name: Setup Node.js environment
       uses: actions/setup-node@main