workflow: run coveralls if PR or main branch

Author: Warashi

.github/workflows/test.yml

@@ -21,6 +21,7 @@ jobs:
       - uses: actions/checkout@v4
       - run: go test -coverprofile=cover.out ./...
       - name: Coveralls GitHub Action
+        if: github.event_name == 'pull_request' || github.ref_name == 'main'
         uses: coverallsapp/github-action@v2
         with:
           file: cover.out