Add support for Python 3.12

Author: hugovk

.github/workflows/tests.yml

@@ -1,14 +1,15 @@
 name: tzdata contents
 
-on: [pull_request]
+on: [push, pull_request, workflow_dispatch]
 
 jobs:
   tests:
 
     runs-on: ${{ matrix.os }}
     strategy:
+      fail-fast: false
       matrix:
-        python-version: ["2.7", "3.6", "3.7", "3.8", "3.9", "3.10", "3.11"]
+        python-version: ["2.7", "3.6", "3.7", "3.8", "3.9", "3.10", "3.11", "3.12"]
         os: ["ubuntu-latest", "windows-latest", "macos-latest"]
         exclude:
           - python-version: "2.7"
@@ -29,6 +30,7 @@ jobs:
       uses: actions/setup-python@v4
       with:
         python-version: ${{ matrix.python-version }}
+        allow-prereleases: true
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
@@ -50,7 +52,7 @@ jobs:
       - name: ${{ matrix.toxenv }}
         uses: actions/setup-python@v4
         with:
-          python-version: "3.10"
+          python-version: "3.x"
       - name: Install tox
         run: |
           python -m pip install --upgrade pip