Update iOS information

- iOS deployment target change from 9.0 to 12.0 by default
- supported lowest version is now 9.0 instead of 8.0
- add auto create build number
3 jobs for 270-21-04-prep in 8 minutes and 18 seconds (queued for 2 seconds)
latest
Status Job ID Name Coverage
  Build
passed #4471
install_dependencies

00:03:30

 
  Lint
passed #4472
lint

00:01:51

 
  Test
passed #4473
test

00:02:56