chore(release): 2.9.0-rc.1

## [2.9.0-rc.1](v2.8.4...v2.9.0-rc.1) (2021-07-08)

### Features

* use createApp api ([7b4dd29](7b4dd29))
* use global api to register components ([eb7e1ad](eb7e1ad))
* use vue 3 global and composition api in ix-img ([0e05aa9](0e05aa9))
* use vue 3 global and composition api in ix-picture ([3c3d626](3c3d626))
* use vue 3 global and composition api in ix-source ([619ed84](619ed84))

### Bug Fixes

* change method name to the correct name ([801b53b](801b53b))
* use attrs destrucuring to access context ([83536d6](83536d6))