get_tag_severity
Description:
Get the severity for a given issue tag.
Parameters:
| this | 
           An instance of Validator.  | 
      
Returns:
| 
           The IssueSeverity  | 
      
Get the severity for a given issue tag.
| this | 
           An instance of Validator.  | 
      
| 
           The IssueSeverity  |