Remove gemspec line for private gems

Author: alexrudall

ruby-openai.gemspec

@@ -11,8 +11,6 @@ Gem::Specification.new do |spec|
   spec.license       = "MIT"
   spec.required_ruby_version = Gem::Requirement.new(">= 2.3.0")
 
-  spec.metadata["allowed_push_host"] = "TODO: Set to 'http://mygemserver.com'"
-
   spec.metadata["homepage_uri"] = spec.homepage
   spec.metadata["source_code_uri"] = "https://github.com/alexrudall/ruby-openai"
   spec.metadata["changelog_uri"] = "https://github.com/alexrudall/ruby-openai/blob/master/CHANGELOG.md"