TST: probe full range of OS/Python combinations

.github/workflows/ci_tests.yml

@@ -5,7 +5,7 @@ on:
   pull_request:
 
 jobs:
-  ci-tests:
+  tests:
     uses: OpenAstronomy/github-actions-workflows/.github/workflows/tox.yml@v1
     with:
       libraries: |
@@ -23,9 +23,36 @@ jobs:
         # Code style
         - linux: codestyle
         # Standard tests
-        - linux: py36-test
         - linux: py38-test
+        - linux: py39-test
+        - macos: py38-test
+        - macos: py39-test
+        - windows: py38-test
+        - windows: py39-test
+
+  allowd_failures:
+    uses: OpenAstronomy/github-actions-workflows/.github/workflows/tox.yml@v1
+    strategy:
+      fail-fast: false
+    with:
+      libraries: |
+        apt:
+          - libxkbcommon-x11-0
+          - libxcb-icccm4
+          - libxcb-image0
+          - libxcb-keysyms1
+          - libxcb-randr0
+          - libxcb-render-util0
+          - libxcb-xfixes0
+          - libxcb-xinerama0
+      envs: |
+        # Tests allowed to fail
+        - linux: py36-test
+        - linux: py37-test
+        - linux: py310-test
         - macos: py36-test
+        - macos: py37-test
         - macos: py310-test
         - windows: py36-test
-        - windows: py39-test
+        - windows: py37-test
+        - windows: py310-test