changed from node@v2-beta to node@v2

Author: nikiOstrov

.github/workflows/buildMain.yml

@@ -48,7 +48,7 @@ jobs:
           repository: devonfw-tutorials/tutorials
           path: playbooks
 
-      - uses: actions/setup-node@v2-beta
+      - uses: actions/setup-node@v2
 
       - name: install TS
         run: npm install typescript