chore: bump msrv to 1.65

[cratelyn]

this crate can no longer be built on 1.63 due to a dependency increasing its own msrv. this commit bumps hyper-util's minimum rust version.

Run cargo check --features full
    Updating crates.io index
 Downloading crates ...
  Downloaded atomic-waker v1.1.2
  Downloaded autocfg v1.4.0
  Downloaded equivalent v1.0.2
  Downloaded fnv v1.0.7
  Downloaded futures-core v0.3.31
  Downloaded futures-task v0.3.31
  Downloaded futures-util v0.3.31
  Downloaded itoa v1.0.15
  Downloaded indexmap v2.8.0
  Downloaded proc-macro2 v1.0.94
  Downloaded pin-project-lite v0.2.16
  Downloaded quote v1.0.40
  Downloaded socket2 v0.5.8
  Downloaded tokio-macros v2.3.0
  Downloaded signal-hook-registry v1.4.2
  Downloaded unicode-ident v1.0.18
  Downloaded try-lock v0.2.5
  Downloaded want v0.3.1
  Downloaded tracing-core v0.1.33
  Downloaded slab v0.4.9
  Downloaded tracing v0.1.41
  Downloaded tower-service v0.3.3
  Downloaded syn v2.0.100
  Downloaded smallvec v1.14.0
  Downloaded pin-utils v0.1.0
  Downloaded tokio v1.38.1
  Downloaded libc v0.2.171
  Downloaded once_cell v1.21.1
  Downloaded mio v0.8.11
  Downloaded hyper v1.6.0
  Downloaded httpdate v1.0.3
  Downloaded httparse v1.10.1
  Downloaded http v1.3.1
  Downloaded hashbrown v0.15.0
  Downloaded h2 v0.4.8
  Downloaded futures-sink v0.3.31
  Downloaded futures-channel v0.3.31
  Downloaded bytes v1.10.1
  Downloaded http-body v1.0.1
  Downloaded tokio-util v0.7.11
error: package `once_cell v1.21.1` cannot be built because it requires rustc 1.65 or newer, while the currently active rustc version is 1.63.0
Error: Process completed with exit code 101.

[seanmonstar]

The way I've handled this in other libraries is to just pin the dependencies in the MSRV job. I think that's fair, since someone who can't upgrade their compiler can still use this library if they pin the dependency too.

[cratelyn]

; cargo +1.63 check --features=full
error: package `tokio v1.43.0` cannot be built because it requires rustc 1.70 or newer, while the currently active rustc version is 1.63.0
; cargo +1.63 check --features=full
error: package `tokio-util v0.7.13` cannot be built because it requires rustc 1.70 or newer, while the currently active rustc version is 1.63.0
; cargo +1.63 check --features=full
error: package `mio v1.0.3` cannot be built because it requires rustc 1.70 or newer, while the currently active rustc version is 1.63.0
; cargo +1.63 check --features=full
error: package `hashbrown v0.15.2` cannot be built because it requires rustc 1.65.0 or newer, while the currently active rustc version is 1.63.0
; cargo +1.63 check --features=full

hm. i'm sympathetic to the philosophy, but i'm not quite sure how to satiate the MSRV errors i see in various crates when i try to compile this crate with 1.63. i see issues with hashbrown, mio, tokio-util, and tokio, most of which are transitive dependencies.

in any case, i'll close this. thanks.

[seanmonstar]

Here's the job in reqwest: https://github.com/seanmonstar/reqwest/blob/96a4fea5fed6e239b7d69334a8a5a824b829536c/.github/workflows/ci.yml#L297