Updating axios in types to be lower case (#2797)

Co-authored-by: NXianming Zhong <chinesedfan@qq.com>

index.d.ts

@@ -155,6 +155,6 @@ export interface AxiosStatic extends AxiosInstance {
   spread<T, R>(callback: (...args: T[]) => R): (array: T[]) => R;
 }
 
-declare const Axios: AxiosStatic;
+declare const axios: AxiosStatic;
 
-export default Axios;
+export default axios;