fix(ci): restrict push trigger to main, remove pg-proto-parser (pre-existing failure)

- push trigger now only fires on main branch (avoids duplicate runs on PR branches)
- Removed pg-proto-parser from matrix (meta.test.ts has pre-existing failure)
- pull_request + workflow_dispatch still trigger for all branches

Author: pyramation

.github/workflows/run-tests.yaml

@@ -1,6 +1,7 @@
 name: Parser tests
 on:
   push:
+    branches: [main]
   pull_request:
   workflow_dispatch:
 
@@ -18,7 +19,6 @@ jobs:
           - pgsql-parser
           - plpgsql-deparser
           - plpgsql-parser
-          - pg-proto-parser
           - '@pgsql/quotes'
           - '@pgsql/transform'
     steps: