Auto merge of #12580 - ehuss:update-git2, r=epage

Update git2

This is a routine update of libgit2.
Changelog: https://github.com/rust-lang/git2-rs/blob/master/CHANGELOG.md#0180---2023-08-28

There is a pretty large number of changes, but I don't think any of them are particularly of interest in terms of changes users will see. Most of the changes are opt-in and we don't opt-in to them (SHA256, Windows schannel, or shallow clone).

Cargo.toml

@@ -38,8 +38,8 @@ curl-sys = "0.4.65"
 filetime = "0.2.21"
 flate2 = { version = "1.0.26", default-features = false, features = ["zlib"] }
 fwdansi = "1.1.0"
-git2 = "0.17.2"
-git2-curl = "0.18.0"
+git2 = "0.18.0"
+git2-curl = "0.19.0"
 gix = { version = "0.45.1", default-features = false, features = ["blocking-http-transport-curl", "progress-tree"] }
 gix-features-for-configuration-only = { version = "0.30.0", package = "gix-features", features = [ "parallel" ] }
 glob = "0.3.1"
@@ -57,7 +57,7 @@ jobserver = "0.1.26"
 lazy_static = "1.4.0"
 lazycell = "1.3.0"
 libc = "0.2.147"
-libgit2-sys = "0.15.2"
+libgit2-sys = "0.16.1"
 libloading = "0.8.0"
 memchr = "2.5.0"
 miow = "0.6.0"