Restore continue-on-error

Author: srittau

.github/workflows/ci.yml

@@ -70,6 +70,7 @@ jobs:
           cd src
           python --version  # just to make sure we're running the right one
           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