Change node version for action to node20 (#866)

action.yml

@@ -33,7 +33,7 @@ outputs:
   node-version:
     description: 'The installed node version.'
 runs:
-  using: 'node16'
+  using: 'node20'
   main: 'dist/setup/index.js'
   post: 'dist/cache-save/index.js'
   post-if: success()