run prover workflow only on PRs

Author: prajwolrg

.github/workflows/prover.yml

@@ -1,10 +1,6 @@
 name: Run prover guest code checks
 
-on:
-  pull_request:
-  merge_group:
-  push:
-    branches: [main]
+on: pull_request
 
 permissions: {}