PKGBASE Upgrade 15.0-RELEASE to 15.1-BETA2

[vermaden]

Hi,

I was not able to find information on how to upgrade FreeBSD 15.0-RELEASE to 
15.1-BETA2 in PKGBASE world.

Its simple and known with freebsd-update(8) but a mystery with PKGBASE.

Please advice.

Thanks,
vermaden