Update github action

.github/workflows/build.yml

@@ -2,6 +2,8 @@ name: Build
 
 on:
   push:
+    branches:
+      - main # create pull request to run actions on other branches
   pull_request:
 
 jobs:
@@ -38,8 +40,9 @@ jobs:
   coverage:
     name: Coverage
     runs-on: ubuntu-latest
+    if: ${{ !github.event.pull_request.head.repo.fork }}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v9.0.0
       - name: Set up Ruby
         uses: ruby/setup-ruby@v1
         with: