Merge "Upgrade regex-syntax to 0.6.28" am: aa41e2c8d7 am: a6de87ad58

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/regex-syntax/+/2349095

Change-Id: I23208febea865fafcfcbba3adce815e4a5f82968
Signed-off-by: Automerger Merge Worker <[email protected]>