[rubygems/rubygems] Bump rb-sys

Bumps [rb-sys](https://github.com/oxidize-rb/rb-sys) from 0.9.90 to 0.9.91.
- [Release notes](https://github.com/oxidize-rb/rb-sys/releases)
- [Commits](https://github.com/oxidize-rb/rb-sys/compare/v0.9.90...v0.9.91)

---
updated-dependencies:
- dependency-name: rb-sys
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

https://github.com/rubygems/rubygems/commit/a84b94b9ec

test/rubygems/test_gem_ext_cargo_builder/rust_ruby_example/Cargo.lock

@@ -145,18 +145,18 @@ dependencies = [
 
 [[package]]
 name = "rb-sys"
-version = "0.9.90"
+version = "0.9.91"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "55d933382388cc7a6fdfd54e222eca7994791ac4b9ce5c9e8df280c739d86bbe"
+checksum = "eb81203e271055178603e243fee397f5f4aac125bcd20036279683fb1445a899"
 dependencies = [
  "rb-sys-build",
 ]
 
 [[package]]
 name = "rb-sys-build"
-version = "0.9.90"
+version = "0.9.91"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ebc5a7e3a875419baaa0d8cc606cdfb9361b444cb7e5abcf0de4693025887374"
+checksum = "9de9403a6aac834e7c9534575cb14188b6b5b99bafe475d18d838d44fbc27d31"
 dependencies = [
  "bindgen",
  "lazy_static",

test/rubygems/test_gem_ext_cargo_builder/rust_ruby_example/Cargo.toml

@@ -7,4 +7,4 @@ edition = "2021"
 crate-type = ["cdylib"]
 
 [dependencies]
-rb-sys = "0.9.90"
+rb-sys = "0.9.91"