chore(bundler-webpack): fix webpack types update

Author: meteorlxy

packages/@vuepress/bundler-webpack/src/build/createBuild.ts

@@ -40,13 +40,13 @@ export const createBuild = (
         if (err) {
           reject(err)
         } else if (stats?.hasErrors()) {
-          stats.toJson().errors.forEach((err) => {
+          stats.toJson().errors?.forEach((err) => {
             console.error(err)
           })
           reject(new Error('Failed to compile with errors'))
         } else {
           if (stats?.hasWarnings()) {
-            stats.toJson().warnings.forEach((warning) => {
+            stats.toJson().warnings?.forEach((warning) => {
               console.warn(warning)
             })
           }

packages/@vuepress/bundler-webpack/src/build/ssr/createClientPlugin.ts

@@ -24,7 +24,9 @@ export const createClientPlugin = (
         'vuepress-client-plugin',
         async (compilation) => {
           // get webpack stats object
-          const stats: StatsToJsonOutput = compilation.getStats().toJson()
+          const stats: StatsToJsonOutput = (compilation
+            .getStats()
+            .toJson() as unknown) as StatsToJsonOutput
 
           const {
             assets = [],