change ways to write validate output

.gitea/workflows/varnish-exporter.yml

@@ -20,7 +20,7 @@ jobs:
           LATEST=`curl --silent https://api.github.com/repos/jonnenauha/prometheus_varnish_exporter/releases/latest | jq -r .tag_name | sed "s/v//"`
           echo "current: $CURRENT"
           echo "latest: $LATEST"
-          if awk "BEGIN {exit !($LATEST > $CURRENT)}"; then echo $LATEST > .version; echo "::set-output name=build::true"; fi
+          if awk "BEGIN {exit !($LATEST > $CURRENT)}"; then echo $LATEST > .version; echo "build=true" >> $GITEA_OUTPUT; fi
 
       - uses: stefanzweifel/git-auto-commit-action@v6
         with: