ci: Bump checkout to v4 (#209)

Author: Jean-BaptisteC

.github/workflows/main.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-20.04
     steps:
     - name: Check out code
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: Lint changelog file
       uses: docker://avtodev/markdown-lint:v1.5