fix(require-explicit-emits): Add support for kebab-cased custom events

[Robo-Rin]

The existing vue/require-explicit-emits rule does not support the scenario where a custom event is emitted in kebab-case. This usage was recommended as a workaround by core Vue members here: vuejs/core#5220 (comment) .

Before this PR with allowProps: true, this works but is ugly and violates vue/prop-name-casing:

props: ['onCustom-event'],
// ...
this.$emit('custom-event')

After this PR you will be able to do:

props: ['onCustomEvent'],
// ...
this.$emit('custom-event')

[Robo-Rin]

Looks like what I thought was working was a false positive. Currently having issues with the recommended strategy from the github issue I linked. Closing for now but will reopen if I can get it working.