Specify dev requirements

Author: bryanmytko

gpsoauth.gemspec

@@ -20,9 +20,9 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
 
-  spec.add_development_dependency "bundler", "~> 1.11"
+  spec.add_development_dependency "bundler", "~> 2.2.11"
   spec.add_development_dependency "byebug", "~> 9.0.5"
   spec.add_development_dependency "rake", "~> 10.0"
-  spec.add_development_dependency "rspec"
-  spec.add_development_dependency "webmock"
+  spec.add_development_dependency "rspec", "~> 3.4"
+  spec.add_development_dependency "webmock", "~> 3.18"
 end