Limit GH actions to only run on push or external PR.

Author: rkistner

.github/workflows/test.yml

@@ -12,6 +12,7 @@ on:
 jobs:
   test-service-container-build:
     name: Build and Test PowerSync Service
+    if: github.event_name == 'push' || (github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name != github.repository)
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
@@ -34,6 +35,7 @@ jobs:
 
   run-core-tests:
     name: Core Test
+    if: github.event_name == 'push' || (github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name != github.repository)
     runs-on: ubuntu-latest
 
     steps: