[joss][ui] numeric input

[anibalsolon]

Part of: openjournals/joss-reviews#6336

Currently, the threshold inputs are of type text. Given you are providing min and max, I assume it will always be a number. I'd suggest to change the field type to "number", so 1) the range is applied, and 2) no other values are provided (e.g. characters).

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

[katjaq]

Thank you for the suggestion. We implemented this change of input type from text to number in commit #ffbda69