[New] Add filename-case rule

[corbinu]

I use unicorn in my eslint-config and its filename-case rule does not work with Vue conventions so this rule replaces it.

I made this part of the recommended set but happy to take any feedback on changes :)

[michalsnik]

Hi @corbinu thanks for working on this. Turns out we have a proposition for a similar rule here: #248 though it's only about Vue components. And because it's eslint plugin for vue I think we should stick here with .vue files only and if you don't want eslint-plugin-unicorn to interfere with your Vue files. it's probably a good idea to update the original rule there with additional setting where you could black list some extensions.

[corbinu]

@michalsnik Unfortunately that has been discussed before and didn't seem to go anywhere sindresorhus/eslint-plugin-unicorn#23

I can try merging over there is a harder pr to write to allow any file to be passed. If it gets through great would just would hate to do all the extra work if they aren't interested

[michalsnik]

I get your point @corbinu , what I proposed was to actually add some kind of ignoreExtenstions setting there so it would simply not check files with given extensions. This way other plugins could utilise their own standards for given files - in our case .vue files. This should be easier to explain and get approval to work on I think :)

And here I'd stick with rule just for .vue files casing anyway.

[corbinu]

@michalsnik That is exactly what was proposed in import unless they want to have an ignore rule will be hard to have a run on just .vue files. Closing for now though