Prerelease changes
- Rename theme packages (PR #15454 by ecraig12345)
- Update Theme instances to contain components/scopedSettings. (PR #15504 by xugao)
- rename @uifabric/variants to @fluentui/scheme-utilities (PR #15598 by xugao)
- Rename @uifabric/set-version to @fluentui/set-version (PR #15616 by tomi-msft)
- Rename office-ui-fabric-react package and update references (PR #15271 by ecraig12345)