Set python-version for pre-commit to remove CI warning

Author: hugovk

.github/workflows/main.yml

@@ -30,4 +30,6 @@ jobs:
     steps:
     - uses: actions/checkout@v3
     - uses: actions/setup-python@v4
+      with:
+        python-version: 3.x
     - uses: pre-commit/[email protected]