terraform/aws module: typo

This is what I get for thinking that the GitHub in-browser editor would
be sufficient. -_-

terraform/aws/consul.tf

@@ -68,6 +68,6 @@ resource "aws_security_group" "consul" {
         from_port = 0
         to_port = 0
         protocol = "-1"
-        cidr_block = "0.0.0.0/0"
+        cidr_blocks = ["0.0.0.0/0"]
     }
 }