dep: bump the min version of mime-types

to one that supports modern ruby.

mechanize.gemspec

@@ -56,7 +56,7 @@ Gem::Specification.new do |spec|
   spec.add_runtime_dependency("addressable", "~> 2.8")
   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("mime-types", "~> 3.3")
   spec.add_runtime_dependency("net-http-digest_auth", ">= 1.4.1", "~> 1.4")
 
   # careful! some folks are relying on older versions of net-http-persistent