Drop no_proxy_fix gem

This gem was only needed to fix [a bug in Ruby 2.4](ruby/ruby#1513),
but since the required Ruby version of this gem is 2.7.0 we do not
need this patch.

danger.gemspec

@@ -27,7 +27,6 @@ Gem::Specification.new do |spec|
   spec.add_runtime_dependency "git", "~> 1.13"
   spec.add_runtime_dependency "kramdown", "~> 2.3"
   spec.add_runtime_dependency "kramdown-parser-gfm", "~> 1.0"
-  spec.add_runtime_dependency "no_proxy_fix"
   spec.add_runtime_dependency "octokit", ">= 4.0"
   spec.add_runtime_dependency "terminal-table", ">= 1", "< 4"
 end

lib/danger/commands/pr.rb

@@ -4,7 +4,6 @@
 require "fileutils"
 require "octokit"
 require "tmpdir"
-require "no_proxy_fix"
 
 module Danger
   class PR < Runner