test: Ensure broken node 16.9.0 isn't used (#960)

Author: eps1lon

.github/workflows/validate.yml

@@ -17,7 +17,8 @@ jobs:
     if: ${{ !contains(github.head_ref, 'all-contributors') }}
     strategy:
       matrix:
-        node: [12, 14, 16]
+        # TODO: relax `'16.9.1'` to `16` once GitHub has 16.9.1 cached. 16.9.0 is broken due to https://github.com/nodejs/node/issues/40030
+        node: [12, 14, '16.9.1']
         react: [latest, next, experimental]
     runs-on: ubuntu-latest
     steps: