Merge pull request #6 from per1234/migrate-set-output

Migrate "Sync Labels" workflow from deprecated `set-output` commands

Author: facchinm

.github/workflows/sync-labels.yml

@@ -108,7 +108,7 @@ jobs:
         run: |
           # Use of this flag in the github-label-sync command will cause it to only check the validity of the
           # configuration.
-          echo "::set-output name=flag::--dry-run"
+          echo "flag=--dry-run" >> $GITHUB_OUTPUT
 
       - name: Checkout repository
         uses: actions/checkout@v3