chore(proxy): update vendored postgres libs to edition 2021 (#10139)

I ran `cargo fix --edition` in each project prior, and it found nothing
that needed fixing.

libs/proxy/postgres-types2/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "postgres-types2"
 version = "0.1.0"
-edition = "2018"
+edition = "2021"
 license = "MIT/Apache-2.0"
 
 [dependencies]

libs/proxy/postgres-types2/src/lib.rs

@@ -2,8 +2,7 @@
 //!
 //! This crate is used by the `tokio-postgres` and `postgres` crates. You normally don't need to depend directly on it
 //! unless you want to define your own `ToSql` or `FromSql` definitions.
-#![doc(html_root_url = "https://docs.rs/postgres-types/0.2")]
-#![warn(clippy::all, rust_2018_idioms, missing_docs)]
+#![warn(clippy::all, missing_docs)]
 
 use fallible_iterator::FallibleIterator;
 use postgres_protocol2::types;