dep: update gem dependencies

Closes #565

mechanize.gemspec

@@ -46,16 +46,16 @@ Gem::Specification.new do |spec|
 
   spec.required_ruby_version = ">= 2.5.0"
 
-  spec.add_runtime_dependency("domain_name", [">= 0.5.1", "~> 0.5"])
-  spec.add_runtime_dependency("http-cookie", ["~> 1.0"])
-  spec.add_runtime_dependency("mime-types", [">= 1.17.2"])
-  spec.add_runtime_dependency("net-http-digest_auth", [">= 1.1.1", "~> 1.1"])
-  spec.add_runtime_dependency("net-http-persistent", [">= 2.5.2"])
-  spec.add_runtime_dependency("nokogiri", ["~> 1.6"])
-  spec.add_runtime_dependency("ntlm-http", [">= 0.1.1", "~> 0.1"])
-  spec.add_runtime_dependency("webrobots", ["< 0.2", ">= 0.0.9"])
-  spec.add_runtime_dependency('addressable', "~> 2.7")
-  spec.add_runtime_dependency('webrick', "~> 1.7")
-
-  spec.add_development_dependency("rubocop", "~> 1.7")
+  spec.add_runtime_dependency("domain_name", ">= 0.5.20190701", "~> 0.5")
+  spec.add_runtime_dependency("http-cookie", ">= 1.0.3", "~> 1.0")
+  spec.add_runtime_dependency("mime-types", "~> 3.0")
+  spec.add_runtime_dependency("net-http-digest_auth", ">= 1.4.1", "~> 1.4")
+  spec.add_runtime_dependency("net-http-persistent", ">= 4.0.1", "~> 4.0")
+  spec.add_runtime_dependency("nokogiri", ">= 1.11.1", "~> 1.11")
+  spec.add_runtime_dependency("ntlm-http", ">= 0.1.1", "~> 0.1")
+  spec.add_runtime_dependency("webrobots", "~> 0.1.2")
+  spec.add_runtime_dependency("addressable", "~> 2.7")
+  spec.add_runtime_dependency("webrick", "~> 1.7")
+
+  spec.add_development_dependency("rubocop", ">= 1.9.1", "~> 1.9")
 end