Update rspec requirement from ~> 3.12.0 to ~> 3.13.0 (#124)

Updates the requirements on [rspec](https://github.com/rspec/rspec-metagem) to permit the latest version.
- [Commits](rspec/rspec-metagem@v3.12.0...v3.13.0)

---
updated-dependencies:
- dependency-name: rspec
  dependency-type: direct:development
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

trino-client.gemspec

@@ -23,7 +23,7 @@ Gem::Specification.new do |gem|
   gem.add_dependency "msgpack", [">= 1.5.1"]
 
   gem.add_development_dependency "rake", [">= 0.9.2", "< 14.0"]
-  gem.add_development_dependency "rspec", "~> 3.12.0"
+  gem.add_development_dependency "rspec", "~> 3.13.0"
   gem.add_development_dependency "webmock", ["~> 3.0"]
   gem.add_development_dependency "addressable", "~> 2.8.1" # 2.5.0 doesn't support Ruby 1.9.3
   gem.add_development_dependency "simplecov", "~> 0.22.0"