Test against Python 3.12 preview

https://dev.to/hugovk/help-test-python-312-beta-1508/

.github/workflows/test.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11"]
+        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12"]
         numpy: [0, 1]
         os: [ubuntu-latest, macos-latest, windows-latest]
     steps:
@@ -19,6 +19,7 @@ jobs:
       uses: actions/setup-python@v4
       with:
         python-version: ${{ matrix.python-version }}
+        allow-prereleases: true
     - uses: actions/cache@v3
       name: Configure pip caching
       with: