Update releases.yml (#960)

.github/workflows/releases.yml

@@ -18,6 +18,11 @@ jobs:
       - name: verify package exists
         run: ls packages/${{ github.event.inputs.package }}
         
+      - name: Set Node.js 12.x
+        uses: actions/setup-node@v1
+        with:
+          node-version: 12.x
+        
       - name: npm install
         run: npm install