AWS::WAFRegional::RegexMatchSet

## 1. Title
AWS::WAFRegional::RegexMatchSet

## 2. Scope of request
AWS::WAFRegional::RegexPatternSet is currently supported in cloudformation but it will need be added to a regex match set resource

## 3. Expected behavior
As mentioned on the cloudformation documentation of AWS::WAFRegional::RegexPatternSet, RegexMatchSet must be done outside of cloudformation using the console, CLI or API calls.

## 4. Suggest specific test cases
It should work similar to AWS::WAFRegional::ByteMatchSet with String matches

## 5. Helpful Links to speed up research and evaluation
ByteMatchSet: https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-wafregional-bytematchset.html
RegexPatternSet: https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-wafregional-bytematchset.html

## 6. Category
Security

## 7. Any additional context
Please update for WAF (Cloudfront) as well.

Start by comparing the AWS::WAFRegional::ByteMatchSet and RegexPatternSet CloudFormation documentation linked in the issue. Determine the required RegexMatchSet resource behavior and test cases, including String matches and the requested WAF CloudFront coverage. Done means both regional and CloudFront WAF resources are supported and covered by tests.

Written by the indexing model from the issue text.