semverOrder function
Returns the comparison order: -1, 0, or 1.
Implementation
int semverOrder(String a, String b) {
final va = SemVer.tryParse(a);
final vb = SemVer.tryParse(b);
if (va == null || vb == null) return 0;
final cmp = va.compareTo(vb);
if (cmp < 0) return -1;
if (cmp > 0) return 1;
return 0;
}