Closes #

#9919

Changelog

Changed

I made a change based off a feature request I proposed and if the idea is worth taking into account, I thought I could take a gamble at it for my first carbon PR and get some experience with contributing to carbon

Basically, we found ourselves allowing file extensions that contain - an _ for our project. Even though we allow it in the accept prop, the built in regex does not allow it. So I thought if we could give he user access to changing/modifying that regex directly to work with what they pass into the accept prop it could help cases like ours. This best making changes to the regex like hard coding things for our need or every person's need that may or may not come a need.

Testing / Reviewing

My attempt at testing was a few things.

Regression test was my main thing. I added the default regex as a default prop to keep default behavior and tested this in a local storybook copy (after modifying the story book) and added unit test.

Thoughts

This idea is something I believe can be useful but i understand if this idea gets thrown out. If it does or does not, if there is any advice for the code or unit test (coding design, style, framework, etc) please let me know so I can learn and do better next time, thanks!