[automerge] Update fastboot version checking to 3103 to support P21 2p: 2573c7ce0a am: 15f0db8ce8 am: 8ea1d48f9e am: f8766d1fe7

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

Change-Id: I529607e9543e9575be2253bce1d67ac373154c56