fix: matrix string

Author: RedTTG

Diff for: .github/workflows/ci.yaml

@@ -15,7 +15,7 @@ jobs:
         os: [ubuntu-latest, macos-latest, windows-latest]
         rust:
           - stable
-        python-version: [3.10, 3.9]
+        python-version: ['3.9', '3.10']
     steps:
       - name: Checkout sources
         uses: actions/checkout@v3