Remove ipaddress dependency

In e8af185 it was added as a dependency
but I can't see where it's used.

Author: ekohl

fog-proxmox.gemspec

@@ -60,6 +60,5 @@ Gem::Specification.new do |spec|
 
   spec.add_dependency 'fog-core',  '~> 2.1'
   spec.add_dependency 'fog-json',  '~> 1.2'
-  spec.add_dependency 'ipaddress', '~> 0.8'
   spec.metadata['rubygems_mfa_required'] = 'true'
 end