build: specified publish only when needed

.gitea/workflows/publish.yml

@@ -1,7 +1,10 @@
 ---
 name: Publish
 run-name: ${{ github.actor }} publish
-on: [push]
+on:
+  push:
+    paths:
+      - 'manifests/**'
 jobs:
   deploy_via_ssh:
     runs-on: ubuntu-latest