build(test.yml): set node-version to 16

Author: gr2m

.github/workflows/test.yml

@@ -26,9 +26,6 @@ jobs:
           cache: npm
       - run: npm ci
       - run: npm test
-
-  # separate job to set as required in branch protection,
-  # as the above change each time the Node versions change
   test:
     runs-on: ubuntu-latest
     needs: test_matrix
@@ -37,5 +34,6 @@ jobs:
       - uses: actions/setup-node@v2
         with:
           cache: npm
+          node-version: 16
       - run: npm ci
-      - run: "npm run validate:ts"
+      - run: npm run validate:ts