Upgrade proc-macro2 to 1.0.56 am: c355513437 am: 0f3d74e8f4 am: 16dcf722d4 am: 1b84c345b4 am: 370d4a3d5a am: 01f4685d44

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/proc-macro2/+/2520717

Change-Id: Id083dd398e72c8695ed51cacfb1e8d90010403c2
Signed-off-by: Automerger Merge Worker <[email protected]>