feat: add Google site verification meta tag in index.html

- Introduced a new meta tag for Google site verification to enhance SEO and improve site indexing.
- This addition supports ongoing efforts to optimize the application's visibility in search results.

Author: zxypro1

docs/index.html

@@ -12,6 +12,7 @@
     <meta name="author" content="zxypro1">
     <meta name="robots" content="index, follow">
     <meta name="msvalidate.01" content="851E8929724BC064EAFA2D4AAE903E09" />
+    <meta name="google-site-verification" content="polTjQtkihIv7LZ-5RVl19ejDTy6ZU9TTX6xiDBKgUg" />
     <link rel="canonical" href="https://zxypro1.github.io/OfflineCodePractice/">
     <link rel="alternate" href="https://zxypro1.github.io/OfflineCodePractice/" hreflang="en">
     <link rel="alternate" href="https://zxypro1.github.io/OfflineCodePractice/zh/" hreflang="zh-CN">