Update tonic-build requirement from =0.12.2 to =0.12.3 (#6473)

* Update tonic-build requirement from =0.12.2 to =0.12.3

Updates the requirements on [tonic-build](https://github.com/hyperium/tonic) to permit the latest version.
- [Release notes](https://github.com/hyperium/tonic/releases)
- [Changelog](https://github.com/hyperium/tonic/blob/master/CHANGELOG.md)
- [Commits](hyperium/tonic@v0.12.2...v0.12.3)

---
updated-dependencies:
- dependency-name: tonic-build
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

* regenerate vendored code

---------

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Andrew Lamb <[email protected]>

Author: dependabot[bot]

arrow-flight/gen/Cargo.toml

@@ -34,4 +34,4 @@ publish = false
 # (and checked in) arrow.flight.protocol.rs from changing
 proc-macro2 = { version = "=1.0.86", default-features = false }
 prost-build = { version = "=0.13.3", default-features = false }
-tonic-build = { version = "=0.12.2", default-features = false, features = ["transport", "prost"] }
+tonic-build = { version = "=0.12.3", default-features = false, features = ["transport", "prost"] }