ci: add Python 3.12 and drop 3.7

.github/workflows/test.yml

@@ -10,7 +10,7 @@ jobs:
     strategy:
       matrix:
         os: ["ubuntu-latest", "windows-latest", "macos-latest"]
-        py: ["3.11", "3.10", "3.9", "3.8", "3.7"]
+        py: ["3.12", "3.11", "3.10", "3.9", "3.8"]
 
     runs-on: ${{ matrix.os }}
     name: Run test with Python ${{ matrix.py }} on ${{ matrix.os }}
@@ -23,6 +23,7 @@ jobs:
         uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.py }}
+          allow-prereleases: true
           cache: "pip"
 
       - name: Build