[automerge] Update fastboot version checking to 3103 to support P21 2p: 2573c7ce0a am: 56d83740c9 am: ba5e8ed70b

Original change: https://googleplex-android-review.googlesource.com/c/device/common/+/15720117

Change-Id: Ic30ee70da6c33f26fab1c713fe1ecdb58bfbfe47