doc: change configure method to init in readme (#17)

Co-authored-by: xiaoweii <xiaoweii@amazom.com>

Author: zhu-xiaowei

README.md

@@ -107,7 +107,7 @@ In addition to the required `appId` and `endpoint`, you can configure other info
 ```typescript
 import { ClickstreamAnalytics, EventMode, PageType } from '@aws/clickstream-web';
 
-ClickstreamAnalytics.configure({
+ClickstreamAnalytics.init({
    appId: "your appId",
    endpoint: "https://example.com/collect",
    sendMode: EventMode.Batch,