Update to point to alpha.19 as presumably that's when the umd folder will be available after the changes in this PR

Author: eoghanmurray

guide.md

@@ -21,7 +21,7 @@ You are recommended to install rrweb via jsdelivr's CDN service:
 Also, you can link to a specific version number that you can update manually:
 
 ```html
-<script src="https://cdn.jsdelivr.net/npm/[email protected].14/umd/rrweb.min.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/[email protected].19/umd/rrweb.min.js"></script>
 ```
 
 #### Only include the recorder code

guide.zh_CN.md

@@ -19,7 +19,7 @@
 也可以在 URL 中指定具体的版本号，例如：
 
 ```html
-<script src="https://cdn.jsdelivr.net/npm/[email protected].14/umd/rrweb.min.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/[email protected].19/umd/rrweb.min.js"></script>
 ```
 
 #### 仅引入录制部分