fix(rules): remove min length from rule desc

With config and rule validation, the minLength of 8 was breaking
some tests and was likely to break both example and real rules. It
has been removed.

rules/salty-dog.yml

@@ -62,7 +62,6 @@ definitions:
         $ref: "salty-dog-meta#/definitions/name-safe"
       desc:
         type: string
-        minLength: 8
         maxLength: 255
       level:
         $ref: "salty-dog-meta#/definitions/log-level"