Give out permissions for misspell in private repos

> reviewdog: fail to get diff: GET https://api.github.com/repos/cloudoperators/shoot-grafter/pulls/6: 403 Resource not accessible by integration []

Author: SuperSandro2000

.github/workflows/checks.yaml

@@ -18,6 +18,7 @@ name: Checks
 permissions:
   checks: write
   contents: read
+  pull-requests: read
 jobs:
   checks:
     name: Checks

internal/ghworkflow/workflow_checks.go

@@ -61,7 +61,8 @@ func checksWorkflow(cfg core.Configuration) {
 			with["ignore"] = fmt.Sprintf("%s,%s", with["ignore"], strings.Join(ignoreWords, ","))
 		}
 
-		w.Permissions.Checks = tokenScopeWrite // for nicer output in pull request diffs
+		w.Permissions.Checks = tokenScopeWrite      // for nicer output in pull request diffs
+		w.Permissions.PullRequests = tokenScopeRead // for private repos
 		j.addStep(jobStep{
 			Name: "Check for spelling errors",
 			Uses: core.MisspellAction,