ci: add node v20 (webpack#226)

Author: ersachin3112

.github/workflows/nodejs.yml

@@ -66,7 +66,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, windows-latest, macos-latest]
-        node-version: [14.x, 16.x, 18.x, 19.x]
+        node-version: [14.x, 16.x, 18.x, 20.x]
         webpack-version: [latest]
 
     runs-on: ${{ matrix.os }}