fix: name of vite mode support more characters

修复vite模式名称不支持下划线的问题

fixed: #1115

build/utils.ts

@@ -50,7 +50,7 @@ export function wrapperEnv(envConf: Recordable): ViteEnv {
  */
 function getConfFiles() {
   const script = process.env.npm_lifecycle_script;
-  const reg = new RegExp('--mode ([a-z]+)');
+  const reg = new RegExp('--mode ([a-z_\\d]+)');
   const result = reg.exec(script as string) as any;
   if (result) {
     const mode = result[1] as string;