chore: run CI on Node 21 (#1461)

Author: SimenB

.github/workflows/nodejs.yml

@@ -71,7 +71,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        node-version: [14.x, 16.x, 18.x, 19.x, 20.x]
+        node-version: [14.x, 16.x, 18.x, 19.x, 20.x, 21.x]
         eslint-version: [7, 8]
         ts-eslint-plugin-version: [5, 6]
         exclude: