REP 149: version element does not support SemVer prereleases

[rotu]

The version attribute is defined as 3 period-separated components "MAJOR.MINOR.PATCH", which superficially looks like a Semantic Version.

It does not support full Semantic Versioning which admits prerelease versions and requires them to be respected for version precedence.

It also prevents SemVer build metadata, though this seems to be less useful since a single platform.xml generally applies to multiple build target platforms and because build metadata is ignored for precedence.