Bump actions/setup-node from v1 to v2.1.2

Bumps [actions/setup-node](https://github.com/actions/setup-node) from v1 to v2.1.2.
- [Release notes](https://github.com/actions/setup-node/releases)
- [Commits](actions/setup-node@v1...c6fd00c)

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

.github/workflows/nodejs.yml

@@ -14,7 +14,7 @@ jobs:
     steps:
     - uses: actions/checkout@v1
     - name: Use Node.js ${{ matrix.node-version }}
-      uses: actions/setup-node@v1
+      uses: actions/setup-node@v2.1.2
       with:
         node-version: ${{ matrix.node-version }}
     - uses: actions/cache@v2