Fix date_eq rule validator to accept a single argument

Author: Fghurayri

lib/mini_defender/rules/date_eq.rb

@@ -13,7 +13,7 @@ def self.signature
   end
 
   def self.make(args)
-    raise ArgumentError, 'Target date is required for date rules.' unless args == 1
+    raise ArgumentError, 'Target date is required for date rules.' unless args.length == 1
 
     self.new(args[0])
   end