Should return "*" instead of ""

[sounisi5011]

semver.validRange() returns "*" for all matching version ranges.

const semver = require('semver')

semver.validRange('x.x.x') === '*'
semver.validRange('*') === '*'
semver.validRange('') === '*'

However, intersect() returns an empty string.

const { intersect } = require('semver-range-intersect')

intersect('x.x.x') === ''
intersect('*') === ''
intersect('') === ''