update itertools 0.11.0 -> 0.12.1

Summary:
[Release Notes for 0.12.0](https://github.com/rust-itertools/itertools/blob/master/CHANGELOG.md#0120)
[Release Notes for 0.12.1](https://github.com/rust-itertools/itertools/blob/master/CHANGELOG.md#0121)

### Breaking
- Made `take_while_inclusive` consume iterator by value ([#709](rust-itertools/itertools#709)) --- there are [2 usages](https://www.internalfb.com/code/search?q=repo%3Afbcode%20take_while_inclusive&lang_filter=rust) in fbcode, verified both manually
- Added `Clone` bound to `Unique` ([#777](rust-itertools/itertools#777)) --- there are [37 usages](https://fburl.com/code/hp7vdlch) in fbcode, CI will tell if it breaks

Reviewed By: anps77

Differential Revision: D64305791

fbshipit-source-id: fe99131b206905133c4d2b75693090f5ce44f4ca

Cargo.toml

@@ -19,7 +19,7 @@ fnv = "1.0"
 globset = { version = "0.4.13", features = ["serde1"] }
 ignore = "0.4"
 indexmap = { version = "2.2.6", features = ["arbitrary", "rayon", "serde"] }
-itertools = "0.11.0"
+itertools = "0.12.1"
 log = { version = "0.4.22", features = ["kv_unstable"] }
 measure_time = "0.8.2"
 monostate = "0.1.8"