chore(dev-server): set clientLogLevel option to silent (#4018)

The `none` option is deprecated and will be removed in the next major https://github.com/webpack/webpack-dev-server/pull/1901/files

(cherry picked from commit edcce6a)

Author: franciscobrba

packages/@vue/cli-service/lib/commands/serve.js

@@ -136,7 +136,7 @@ module.exports = (api, options) => {
 
     // create server
     const server = new WebpackDevServer(compiler, Object.assign({
-      clientLogLevel: 'none',
+      clientLogLevel: 'silent',
       historyApiFallback: {
         disableDotRule: true,
         rewrites: genHistoryApiFallbackRewrites(options.publicPath, options.pages)