Drop environments/production from the start of file names

Author: Kevin Paulisse

lib/octocatalog-diff/catalog.rb

@@ -222,7 +222,7 @@ def format_source_file_line(source_file, line_number)
       else
         source_file
       end
-      "(#{filename}:#{line_number})"
+      "(#{filename.sub(%r{^environments/production/}, '')}:#{line_number})"
     end
 
     # Private method: Format the missing references into human-readable text