dev: add .github directory to sparse-checkout for megalinter

The Practicalli Megalinter configuration does not seem to be applied
when running the GitHub workflow

It is assumed that the sparse-checkout is not including the
`.github/` directory an therefore the `.github/config/megalinter.yaml`
file is not available

Add `.github` as a directory in the sparse-checkout directive

.github/workflows/megalinter.yaml

@@ -34,6 +34,7 @@ jobs:
           sparse-checkout: |
             docs
             overrides
+            .github
       - run: echo "🐙 ${{ github.repository }} repository was cloned to the runner."
       # MegaLinter Configuration
       - name: MegaLinter Run