Update README.md

[Shengming-Yan]

✌️

/cc @zendesk/vegemite

Description

Describe the original problem and the changes made on this PR.

Tasks

• Include comments/inline docs where appropriate
• Add unit tests
• Update changelog here
• Add label from one of 'patch'/'minor'/'major' if you want to create a release when merged

References

• JIRA: https://zendesk.atlassian.net/browse/VEG-XXX

DevQA Steps

• Make sure Zendesk Apps Framework regression tests are passing with this change.
• Add specific DevQA instructions here ....

NOTE: DevQA steps are to be actioned only once code has been reviewed and approved.

Risks

• [HIGH | medium | low] Does it work across browsers (including IE!)?
• [HIGH | medium | low] Does it work in the different products (Support, Chat, Connect)?
• [HIGH | medium | low] Are there any performance implications?
• [HIGH | medium | low] Any security risks?
• [HIGH | medium | low] What features does this touch?

Rollback Plan

1. Quickly roll back to the prior release so that customers can refresh to resolve their issue.
2. Revert this PR to restore the master branch to a deployable green state.
3. Notify the author.