ci: add node 21.x

Signed-off-by: Christian Stewart <[email protected]>

Author: paralin

.github/workflows/tests.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node: [18.x]
+        node: [18.x, 21.x]
     timeout-minutes: 10
     steps:
       - name: Harden Runner