gha/sync-cli-docs: Only trigger on relevant PRs

Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>

Author: vvoland

.github/workflows/sync-cli-docs.yml

@@ -11,6 +11,9 @@ on:
         required: false
         default: ""
   pull_request:
+    paths:
+      - '.github/workflows/sync-cli-docs.yml'
+      - 'hack/sync-cli-docs.sh'
 
 permissions:
   contents: write