Test against Python 3.12-dev

Author: hukkin

.github/workflows/tests.yaml

@@ -32,9 +32,9 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        python-version: ['pypy-3.7', '3.7', '3.8', '3.9', '3.10', '3.11']
+        python-version: ['pypy-3.7', '3.7', '3.8', '3.9', '3.10', '3.11', '3.12-dev']
         os: [ubuntu-latest, macos-latest, windows-latest]
-    continue-on-error: ${{ matrix.python-version == '3.11-dev' }}
+    continue-on-error: ${{ matrix.python-version == '3.12-dev' }}
 
     steps:
     - uses: actions/checkout@v3