downgrade actions/checkout

Author: kazupon

.github/workflows/release.yml

@@ -11,7 +11,7 @@ jobs:
     if: github.event.pull_request.merged == true && contains(github.event.pull_request.labels.*.name, 'release')
     runs-on: Ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v1
       - uses: actions/setup-node@v1
         with:
           registry-url: "https://registry.npmjs.org"