fix: Fix link format in README.md (#385)

README.md

@@ -186,7 +186,7 @@ main();
 ```
 
 #### Handling token events
-This library will automatically obtain an `access_token`, and automatically refresh the `access_token` if a `refresh_token` is present.  The `refresh_token` is only returned on the [first authorization]((https://github.com/google/google-api-nodejs-client/issues/750#issuecomment-304521450), so if you want to make sure you store it safely. An easy way to make sure you always store the most recent tokens is to use the `tokens` event:
+This library will automatically obtain an `access_token`, and automatically refresh the `access_token` if a `refresh_token` is present.  The `refresh_token` is only returned on the [first authorization](https://github.com/google/google-api-nodejs-client/issues/750#issuecomment-304521450), so if you want to make sure you store it safely. An easy way to make sure you always store the most recent tokens is to use the `tokens` event:
 
 ```js
 const client = await auth.getClient();