Update main.yml

add Python 3.11, use latest version of GHAs

Author: petercorke

.github/workflows/main.yml

@@ -20,17 +20,17 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [windows-latest, ubuntu-latest, macos-latest]
-        python-version: [3.7, 3.8, 3.9, '3.10']
+        os: [windows-latest, ubuntu-latest, macos-13]
+        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11"]
 
     steps:
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v1
+      uses: actions/setup-python@v5
       with:
         python-version: ${{ matrix.python-version }}
 
     - name: Checkout master branch
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
 
     - name: Install dependencies
       run: |