Initial import of percent-encoding v2.1.0 am: 86d7986f55 am: c299b75b3e am: 23b37b16e8

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/percent-encoding/+/1533063

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I1b269ad527f7ae3c3727a9c903e399f06ed55cf6