Update rugged requirement from >= 0.27, < 1.8 to >= 0.27, < 1.10

Updates the requirements on [rugged](https://github.com/libgit2/rugged) to permit the latest version.
- [Release notes](https://github.com/libgit2/rugged/releases)
- [Changelog](https://github.com/libgit2/rugged/blob/master/CHANGELOG.md)
- [Commits](libgit2/rugged@v0.27.0...v1.9.0)

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

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

undercover.gemspec

@@ -30,5 +30,5 @@ Gem::Specification.new do |spec|
   spec.add_dependency 'bigdecimal'
   spec.add_dependency 'imagen', '>= 0.2.0'
   spec.add_dependency 'rainbow', '>= 2.1', '< 4.0'
-  spec.add_dependency 'rugged', '>= 0.27', '< 1.8'
+  spec.add_dependency 'rugged', '>= 0.27', '< 1.10'
 end