chore: use same node as the publish workflow

.github/workflows/copy-build-to-d2-ci.yml

@@ -27,7 +27,7 @@ jobs:
             - name: Set up Node.js
               uses: actions/setup-node@v1
               with:
-                  node-version: '16.x'
+                  node-version: 12.x
 
             - name: Install dependencies
               run: yarn install --frozen-lockfile