chore(ci): add node 21

Author: mjeanroy

.github/workflows/build.yml

@@ -30,7 +30,7 @@ jobs:
     strategy:
       matrix:
         os: [ windows-latest, ubuntu-latest, macos-latest ]
-        node: [ 18, 19, 20 ]
+        node: [ 18, 19, 20, 21 ]
     steps:
       - uses: actions/checkout@v4.1.1
       - uses: actions/setup-node@v4.0.2