Caniuse: Add support columns for Firefox on iOS

[valioDOTch]

Please consider adding a support column for Firefox on iOS if possible.

[Fyrd]

As with Chrome on iOS, support is ~99% the same as Safari on iOS as it uses the same underlying engine. So not a priority to add this.

[googol7]

@Fyrd OK but some official hint would be nice though.

https://caniuse.com/#feat=input-datetime says for Firefox:
_Partial support refers to supporting date and time input types, but not datetime-local, month or week._

On iOS 12.0 Firefox Version 13.2 (11866) supports type="date", type="time", type="datetime-local", type="month" and displays the native widgets - which is very nice and good to know. type="week" doesn’t seem to be supported.

Tests: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/input/

[trych]

As with Chrome on iOS, support is ~99% the same as Safari on iOS as it uses the same underlying engine. So not a priority to add this.

Like seriously, this info is super hard to find, would be nice to have a little footnote somewhere explaining this.