Allow -dev versions to fail

Author: srittau

.github/workflows/ci.yml

@@ -72,6 +72,7 @@ jobs:
           # accidentally pick up typing_extensions as installed by a dependency
           cd src
           python -m unittest test_typing_extensions.py
+        continue-on-error: ${{ endsWith(matrix.python-version, '-dev') }}
 
       - name: Test CPython typing test suite
         # Test suite fails on PyPy even without typing_extensions
@@ -81,6 +82,7 @@ jobs:
           # Run the typing test suite from CPython with typing_extensions installed,
           # because we monkeypatch typing under some circumstances.
           python -c 'import typing_extensions; import test.__main__' test_typing -v
+        continue-on-error: ${{ endsWith(matrix.python-version, '-dev') }}
 
   linting:
     name: Lint