Update setup-node GH action

Signed-off-by: Stefan Prodan <[email protected]>

Author: stefanprodan

.github/workflows/main.yml

@@ -13,7 +13,9 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v2
     - name: Setup Node.js
-      uses: actions/[email protected]
+      uses: actions/setup-node@v2-beta
+      with:
+        node-version: '12.x'
     - name: Run lint
       run: |
         make lint