Prevent Python 3.12 from blocking checks.

Author: jaraco

.github/workflows/main.yml

@@ -59,6 +59,7 @@ jobs:
         - python: pypy3.9
           platform: ubuntu-latest
     runs-on: ${{ matrix.platform }}
+    continue-on-error: ${{ matrix.python == '3.12' }}
     steps:
       - uses: actions/checkout@v3
       - name: Setup Python