Allow to set the accept input attribute to arbitrary values

[mayjs]

This supersedes #750.
It still solves #546 but may also prove to be useful in other scenarios by allowing to set more mediatypes.

[svenstaro]

Pretty neat and clean! I'd almost be happy to accept it as is but I think this feature is complex enough to require another example line of documentation in the README and also I'd like to see a test for this. The test should be rather simple and you can copy from the existing body of tests.

[mayjs]

Thanks for the feedback!

I added some tests and a line for the README.
How / when do you update the USAGE section in the README?
Is that something you do when a new release is created or should I adjust that part as well?
I was worried about the version number.

Are the tests fine for you or did you have something else in mind?
Thanks for making me write them, that way I learned about rstest and how easily you can do fixture-based testing and parametrized tests using it 🙂.

[svenstaro]

Don't worry about updating the usage, I will do it with the next release. :)

[svenstaro]

Almost there! :)