specify rake-compiler version

mikunyan.gemspec

@@ -32,6 +32,6 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'bundler', '~> 2'
   spec.add_development_dependency 'oily_png', '~> 1'
   spec.add_development_dependency 'pry', '~> 0'
-  spec.add_development_dependency 'rake-compiler'
+  spec.add_development_dependency 'rake-compiler', '~> 1'
   spec.add_development_dependency 'usamin', '~> 7'
 end