cargo: use neon branch of rust-postgres (#9757)

## Problem

We are pining our fork of rust-postgres to a commit hash and that
prevents us from making
further changes to it. The latest commit in rust-postgres requires
#8747,
but that seems to have gone stale. I reverted rust-postgres `neon`
branch to the pinned commit in
neondatabase/rust-postgres#31.

## Summary of changes

Switch back to using the `neon` branch of the rust-postgres fork.

Cargo.toml

@@ -203,21 +203,10 @@ env_logger = "0.10"
 log = "0.4"
 
 ## Libraries from neondatabase/ git forks, ideally with changes to be upstreamed
-
-# We want to use the 'neon' branch for these, but there's currently one
-# incompatible change on the branch. See:
-#
-# - PR #8076 which contained changes that depended on the new changes in
-#   the rust-postgres crate, and
-# - PR #8654 which reverted those changes and made the code in proxy incompatible
-#   with the tip of the 'neon' branch again.
-#
-# When those proxy changes are re-applied (see PR #8747), we can switch using
-# the tip of the 'neon' branch again.
-postgres = { git = "https://github.com/neondatabase/rust-postgres.git", rev = "20031d7a9ee1addeae6e0968e3899ae6bf01cee2" }
-postgres-protocol = { git = "https://github.com/neondatabase/rust-postgres.git", rev = "20031d7a9ee1addeae6e0968e3899ae6bf01cee2" }
-postgres-types = { git = "https://github.com/neondatabase/rust-postgres.git", rev = "20031d7a9ee1addeae6e0968e3899ae6bf01cee2" }
-tokio-postgres = { git = "https://github.com/neondatabase/rust-postgres.git", rev = "20031d7a9ee1addeae6e0968e3899ae6bf01cee2" }
+postgres = { git = "https://github.com/neondatabase/rust-postgres.git", branch = "neon" }
+postgres-protocol = { git = "https://github.com/neondatabase/rust-postgres.git", branch = "neon" }
+postgres-types = { git = "https://github.com/neondatabase/rust-postgres.git", branch = "neon" }
+tokio-postgres = { git = "https://github.com/neondatabase/rust-postgres.git", branch = "neon" }
 
 ## Local libraries
 compute_api = { version = "0.1", path = "./libs/compute_api/" }
@@ -255,7 +244,7 @@ tonic-build = "0.12"
 [patch.crates-io]
 
 # Needed to get `tokio-postgres-rustls` to depend on our fork.
-tokio-postgres = { git = "https://github.com/neondatabase/rust-postgres.git", rev = "20031d7a9ee1addeae6e0968e3899ae6bf01cee2" }
+tokio-postgres = { git = "https://github.com/neondatabase/rust-postgres.git", branch = "neon" }
 
 ################# Binary contents sections
 

workspace_hack/Cargo.toml

@@ -58,7 +58,7 @@ num-integer = { version = "0.1", features = ["i128"] }
 num-traits = { version = "0.2", features = ["i128", "libm"] }
 once_cell = { version = "1" }
 parquet = { version = "53", default-features = false, features = ["zstd"] }
-postgres-types = { git = "https://github.com/neondatabase/rust-postgres.git", rev = "20031d7a9ee1addeae6e0968e3899ae6bf01cee2", default-features = false, features = ["with-serde_json-1"] }
+postgres-types = { git = "https://github.com/neondatabase/rust-postgres.git", branch = "neon", default-features = false, features = ["with-serde_json-1"] }
 prost = { version = "0.13", features = ["prost-derive"] }
 rand = { version = "0.8", features = ["small_rng"] }
 regex = { version = "1" }
@@ -78,7 +78,7 @@ sync_wrapper = { version = "0.1", default-features = false, features = ["futures
 tikv-jemalloc-sys = { version = "0.5" }
 time = { version = "0.3", features = ["macros", "serde-well-known"] }
 tokio = { version = "1", features = ["fs", "io-std", "io-util", "macros", "net", "process", "rt-multi-thread", "signal", "test-util"] }
-tokio-postgres = { git = "https://github.com/neondatabase/rust-postgres.git", rev = "20031d7a9ee1addeae6e0968e3899ae6bf01cee2", features = ["with-serde_json-1"] }
+tokio-postgres = { git = "https://github.com/neondatabase/rust-postgres.git", branch = "neon", features = ["with-serde_json-1"] }
 tokio-rustls = { version = "0.26", default-features = false, features = ["logging", "ring", "tls12"] }
 tokio-stream = { version = "0.1", features = ["net"] }
 tokio-util = { version = "0.7", features = ["codec", "compat", "io", "rt"] }