Merge "Increment platform-tools version to 31.0.0." am: cfacb78776 am: 58c5cdc32a am: 2987b19664

Original change: https://android-review.googlesource.com/c/platform/development/+/1564416

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Ic827e9dc6ccb2c0c0e4583fe99af87c5999d9fa4