Update cxx from 1.0.76 to 1.0.81

Summary:
Release notes:

- https://github.com/dtolnay/cxx/releases/tag/1.0.77
- https://github.com/dtolnay/cxx/releases/tag/1.0.78
- https://github.com/dtolnay/cxx/releases/tag/1.0.79
- https://github.com/dtolnay/cxx/releases/tag/1.0.80
- https://github.com/dtolnay/cxx/releases/tag/1.0.81

Fixes this bug report from Eddie:

{F793474902}

Reviewed By: edward-shen

Differential Revision: D41129523

fbshipit-source-id: 3bbb0b110608c526e7808b8fdae3d2b21bc797b7

Author: David Tolnay

shed/services/common/Cargo.toml

@@ -15,5 +15,5 @@ license = "MIT OR Apache-2.0"
 path = "lib.rs"
 
 [dependencies]
-cxx = "1.0.76"
+cxx = "1.0.81"
 thiserror = "1.0.36"