Bump actions/setup-node from 2 to 2.1.5

Bumps [actions/setup-node](https://github.com/actions/setup-node) from 2 to 2.1.5.
- [Release notes](https://github.com/actions/setup-node/releases)
- [Commits](https://github.com/actions/setup-node/compare/v2...v2.1.5)

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/main.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - uses: actions/setup-node@v2
+      - uses: actions/setup-node@v2.1.5
         with:
           node-version: 12.x
       - run: yarn