[automerge] Update fastboot version checking to 3103 to support P21 2p: 2573c7ce0a am: 15f0db8ce8

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

Change-Id: Ifb96ba1501e1a8a159b9862afc9de5eac3b8065a