Bump version and update changelog

[timmydoza]

Contributing to Twilio

All third party contributors acknowledge that any contributions they provide will be made under the same open source license that the open source project is provided under.

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Pull Request Details

JIRA link(s):

-N/A

Description

This PR prepares the release of version 0.5.1 of the app. Link to changelog here: https://github.com/twilio/twilio-video-app-react/blob/prep-0.5.1-release/CHANGELOG.md

Burndown

Before review

• [ ] Updated CHANGELOG.md if necessary
• [ ] Added unit tests if necessary
• [ ] Updated affected documentation
• [ ] Verified locally with npm test
• [ ] Manually sanity tested running locally
• [ ] Included screenshot as PR comment (if needed)
• [ ] Ready for review

Before merge

• [ ] Got one or more +1s
• [ ] Re-tested if necessary