chore: add back ignore check to allow deploys when changing plugin without changing demo site

Author: pieh

Diff for: demo/netlify.toml

@@ -1,7 +1,7 @@
 [build]
 command = "npm run build"
 publish = "public/"
-# ignore = "git diff --quiet $CACHED_COMMIT_REF $COMMIT_REF . ../plugin/"
+ignore = "git diff --quiet $CACHED_COMMIT_REF $COMMIT_REF . ../plugin/"
 
 [[plugins]]
 package = "../plugin/src/index.ts"