Remove unused rake dependency

Author: rastating

Rakefile

@@ -2,8 +2,8 @@
 
 Gem::Specification.new do |s|
   s.name = 'wpxf'
-  s.version = '2.0.0a'
-  s.date = '2018-07-12'
+  s.version = '2.0.0-alpha.1'
+  s.date = '2018-07-14'
   s.summary = 'WordPress Exploit Framework'
   s.description = 'A Ruby framework designed to aid in the penetration testing of WordPress systems'
   s.authors = ['rastating']
@@ -17,7 +17,6 @@ Gem::Specification.new do |s|
   s.add_dependency 'colorize', '~> 0.8'
   s.add_dependency 'mime-types', '~> 3.1'
   s.add_dependency 'nokogiri', '~> 1.8'
-  s.add_dependency 'rake', '~> 12.3'
   s.add_dependency 'require_all', '~> 2.0'
   s.add_dependency 'rubyzip', '~> 1.2'
   s.add_dependency 'sequel', '~> 5.9'