Quote python versions

Author: ivankravets

.github/workflows/main.yml

@@ -8,7 +8,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest, macos-latest]
-        python-version: [3.7, 3.8, 3.9, 3.10, 3.11]
+        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11"]
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v3