ci: fix action ref

Author: EndBug

.github/workflows/export-labels.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: EndBug/export-label-config@v1
+      - uses: EndBug/export-label-config@main
         with:
           # This is needed if you're dealing with private repos.
           token: ${{ secrets.GITHUB_TOKEN }}