ci: only fetch target branch for commitlint

.woodpecker/checks.yaml

@@ -57,7 +57,7 @@ steps:
     image: *node_image
     commands:
       - <<: *enable_pnpm
-      - git fetch
+      - git fetch origin ${CI_COMMIT_TARGET_BRANCH}
       - pnpm exec commitlint --from origin/${CI_COMMIT_TARGET_BRANCH}
     when:
       event: pull_request