Fixed npm install

Author: SchettlerKoehler

.github/workflows/syntaxCheckPullRequest.yml

@@ -13,6 +13,8 @@ jobs:
         uses: actions/checkout@v2
       - name: Install node environment
         uses: actions/setup-node@v2-beta
+        with:
+          node-version: '12'
       - name: npm install
         run: npm install
       - name: Select Changed Files