Material-ui: CardHeader is missing action property

[liesislukas]

• [x] I have searched the issues of this repository and believe that this is not a duplicate.

https://material-ui-next.com/api/card-header/

CardHeader allows to put in the title, subheader, and avatar but no way to add action button.

Yes, i can use workarounds, create some css etc but i believe it should be solved elegantly with action property.

[lukePeavey]

@oliviertassinari can i take a shot at implementing this?

[mbrookes]

@lukePeavey Great!

[lukePeavey]

@mbrookes ok, i'll give it try!

[lukePeavey]

@mbrookes
@oliviertassinari
I finished an initial draft of the changes. I just pulled the latest changes from v1-beta so my branch would be up to date. A whole bunch of tests are failing now, but im getting the same result on the latest version of v1-beta. Should i go ahead and submit the PR?

[mbrookes]

@lukePeavey Feel free to submit your PR so we can take a look and give feedback. If the test failures are coming from the v1-beta branch, you'll be able to rebase once that's resolved, before we merge.

[lukePeavey]

@mbrookes I submitted an initial PR.