Remove different pandas versioning

lib/docs/scrapers/pandas.rb

@@ -2,6 +2,8 @@ module Docs
   class Pandas < UrlScraper
     self.name = 'pandas'
     self.type = 'sphinx'
+    self.release = '0.18.1'
+    self.base_url = "http://pandas.pydata.org/pandas-docs/version/#{self.release}/"
     self.root_path = 'index.html'
     self.links = {
       home: 'http://pandas.pydata.org/',
@@ -22,9 +24,5 @@ module Docs
       Licensed under the 3-clause BSD License.
     HTML
 
-    version '0.18' do
-      self.release = '0.18.1'
-      self.base_url = "http://pandas.pydata.org/pandas-docs/version/#{self.release}/"
-    end
   end
 end