fix(uni-app-x web): 调整build target支持低版本浏览器

packages/uni-h5-vite/src/plugin/config.ts

@@ -89,9 +89,10 @@ export function createConfig(options: {
         external,
       },
       build: {
-        target: process.env.UNI_APP_X
-          ? ['es2015', 'edge79', 'firefox62', 'chrome64', 'safari11.1']
-          : undefined,
+        target:
+          process.env.UNI_APP_X === 'true'
+            ? ['es2015', 'edge79', 'firefox62', 'chrome64', 'safari11.1']
+            : undefined,
         rollupOptions: {
           // resolveSSRExternal 会判定package.json，hbx 工程可能没有，通过 rollup 来配置
           external: isSsr(env.command, config) ? external : [],