chore(ci): disable lint goheader step on non-pull-request events (#143)

- Pin golangci-lint action to v6 now that goheader doesn't run on the default branch pushes
- This addresses the goheader step misbehaving and linting all files on pushes

Author: qdm12

.github/workflows/lint.yml

@@ -34,11 +34,12 @@ jobs:
         with:
           go-version-file: "go.mod"
       - name: goheader
+        if: ${{ github.event_name == 'pull_request' }}
         # The goheader linter is only enabled in the CI so that it runs only on modified or new files
         # (see only-new-issues: true). It is disabled in .golangci.yml because
         # golangci-lint running locally is not aware of new/modified files compared to the base
         # commit of a pull request, and we want to avoid reporting invalid goheader errors.
-        uses: golangci/golangci-lint-action@ec5d18412c0aeab7936cb16880d708ba2a64e1ae # v6.2.0 since v6.3.1 does not handle `only-new-issues` correctly
+        uses: golangci/golangci-lint-action@v6
         with:
           version: v1.60
           only-new-issues: true