ci: fully remove version matrix

Author: miles-grant-ibigroup

.github/workflows/node-ci.yml

@@ -8,7 +8,7 @@ jobs:
 
     steps:
       - uses: actions/checkout@v2
-      - name: Use Node.js ${{ matrix.node-version }}
+      - name: Use Node.js 14
         uses: actions/setup-node@v2
         with:
           node-version: 14.x