Summary:
Updates `CHANGELOG.md` and bumps version in `package.json` to `0.11.5` to get the package ready for publishing to npm.
Pull Request resolved: https://github.com/facebook/draft-js/pull/2367

Test Plan:
```
yarn
npm publish --dry-run
```

Also played around with "universal" and "playground" examples. They are working.

Reviewed By: claudiopro

Differential Revision: D20671951

Pulled By: mrkev

fbshipit-source-id: 4c68d0fc40a6f5a7a52b38cf4df4782cac23d7f7