Bump actions/setup-node from v1 to v2.1.5

Bumps [actions/setup-node](https://github.com/actions/setup-node) from v1 to v2.1.5.
- [Release notes](https://github.com/actions/setup-node/releases)
- [Commits](actions/setup-node@v1...46071b5)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/seocheck.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - uses: actions/setup-node@v1
+      - uses: actions/setup-node@v2.1.5
         with:
           version: 12
       - name: Markdown SEO Check