Log Message:
net/ruby-twitter: update to 7.0.0

Update ruby-twitter to 7.0.0.

7.0.0
* Add Twitter::DirectMessageEvent (@FabienChaynes)
* Create Twitter::DirectMessageEvent with media (@FabienChaynes)
* Support for DM welcome messages (@FabienChaynes)
* Support for closing Twitter::Streaming::Connection (@okkez)
* Add Twitter::REST::Client#create_direct_message_event (@cyu)
* Add Twitter::REST::Client#premium_search
* Add Twitter::REST::AccountActivity
* Update all direct message methods to return Twitter::DirectMessageEvent
  (@flikglick)
* Correctly handle different Twitter::Error::AlreadyRetweeted error messages
  (@knu)
* Fix proxy setting sample (@nicklegr)
* Add Active Support presence methods on Twitter::NullObject (@davebrace)
* Upload GIFs over 5MB in chunks (@wild_dmitry)
* Track rate limit when searching tweets (@dsalahutdinov1)
* Add quote_count and reply_count attributes to Twitter::Tweet
* Drop support for Ruby 2.0, 2.1, and 2.2