ci: remove set-output

Author: devchenyan

.github/workflows/check_checksums.yml

@@ -31,7 +31,7 @@ jobs:
           body="${body//'%'/'%25'}"
           body="${body//$'\n'/'%0A'}"
           body="${body//$'\r'/'%0D'}"
-          echo ::set-output name=body::$body
+          echo body=$body >> $GITHUB_OUTPUT
 
       - uses: peter-evans/commit-comment@v2
         with: