Update no-important-files-changed.yml (#242)

Author: BNAndras

.github/workflows/no-important-files-changed.yml

@@ -17,7 +17,7 @@ permissions:
 
 jobs:
   check:
-    uses: exercism/github-actions/.github/workflows/check-no-important-files-changed.yml@use-explicit-upstream
+    uses: exercism/github-actions/.github/workflows/check-no-important-files-changed.yml@main
     with:
       repository: ${{ github.event.pull_request.head.repo.owner.login }}/${{ github.event.pull_request.head.repo.name }}
       ref: ${{ github.head_ref }}