update node version syntax in address service validate workflow

.github/workflows/validate-address-service.yaml

@@ -8,9 +8,6 @@ on:
     #   - "address-service/package*.json"
   workflow_dispatch:
 
-env:
-  NODE_VERSION: "12"
-
 defaults:
   run:
     working-directory: ./address-service
@@ -23,7 +20,7 @@ jobs:
       - uses: actions/checkout@main
       - uses: actions/setup-node@main
         with:
-          node-version: ${NODE_VERSION}
+          node-version: "12"
       - name: Install dependencies
         run: npm ci
       - name: Unit tests w/ coverage