Add lint-baseline to prevent build error
The targetSdkVersion should keep 29 to avoid breaking loader, but it will raise a lint error when building because Google Play Store needs it bumps to 30. By following https://developer.android.com/studio/write/lint#snapshot to add lint-baseline.xml for this project to avoid lint error. When we fixed the problem that loader can't work with targetSdkVersion 30, we can remove related issue from lint-baseline.xml.