Run the build workflow on the full mesh branch, too

Otherwise CD on the full mesh branch never happens

.github/workflows/build.yaml

@@ -2,7 +2,7 @@ name: Build
 on:
   pull_request: {}
   push:
-    branches: [livekit]
+    branches: [livekit, full-mesh]
 jobs:
   build:
     name: Build