rename gem creation to "package" instead of "build"

Rakefile

@@ -16,17 +16,17 @@ require "middleman-deploy/pkg-info"
 PACKAGE = "#{Middleman::Deploy::PACKAGE}"
 VERSION = "#{Middleman::Deploy::VERSION}"
 
-task :build do
+task :package do
   system "gem build #{PACKAGE}.gemspec"
 end
 
-task :install => :build do
+task :install => :package do
   Dir.chdir("pkg") do
     system "gem install #{PACKAGE}-#{VERSION}"
   end
 end
 
-task :release => :build do
+task :release => :package do
   Dir.chdir("pkg") do
     system "gem push #{PACKAGE}-#{VERSION}"
   end