changed versions to string

Author: mxaviersmp

.github/workflows/lint_and_test.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.7, 3.8, 3.9, 3.10]
+        python-version: ['3.7', '3.8', '3.9', '3.10']
     steps:
       - uses: actions/checkout@main
       - uses: actions/setup-python@main