Description of problem:  Error message while installing OCP 4.0 with cluster name vicky4.0
~~~
ERROR Error: module.vpc.aws_lb.api_external: only alphanumeric characters and hyphens allowed in "name": "vicky4.0-ext" 
~~~

if we type any special character to the installer for creating install-config it show's "-" or "." is allowed.

But in aws environment, it's creating  module.vpc.aws_lb.api_external which allows only "-" 

Custer name help:
???? The name of the cluster.  This will be used when generating sub-domains.
X Sorry, your reply was invalid: a DNS-1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'example.com', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*')
? Cluster Name [? for help]