Add new line at the end of file if needed

Author: devxoul

lib/poeditor/core.rb

@@ -85,6 +85,9 @@ def export(api_key:, project_id:, language:, type:, tags:nil)
         content.gsub!(/(%(\d+\$)?)@/, '\1s')  # %@ -> %s
       end
 
+      unless content.end_with? "\n"
+        content += "\n"
+      end
       return content
     end