Merge "Warn on `repo upload` if you're not uploading to AOSP master." am: 026eb31f80 am: fa27392f8a am: 361f8f4118

Original change: https://android-review.googlesource.com/c/platform/bootable/recovery/+/1834836

Change-Id: I13dad035e3ae763f4acdcfb77e715671708d2a92