Update bindgen requirement from 0.69 to 0.70

Updates the requirements on [bindgen](https://github.com/rust-lang/rust-bindgen) to permit the latest version.
- [Release notes](https://github.com/rust-lang/rust-bindgen/releases)
- [Changelog](https://github.com/rust-lang/rust-bindgen/blob/main/CHANGELOG.md)
- [Commits](rust-lang/rust-bindgen@v0.69.0...v0.70.0)

---
updated-dependencies:
- dependency-name: bindgen
  dependency-type: direct:production
...

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

gdal-sys/Cargo.toml

@@ -14,6 +14,6 @@ links="gdal"
 libc = "0.2"
 
 [build-dependencies]
-bindgen = { version = "0.69", optional = true }
+bindgen = { version = "0.70", optional = true }
 pkg-config = "0.3"
 semver = "1.0"