[oe] Adding recipes to former meta-openembedded releases

[Stanislav Angelovič]

Hi,

I'm about to send a PR introducing a new recipe for sdbus-c++ library to
meta-openembedded master. I'd also like to support previous releases -
sumo, thud, warrior, where the recipe differs a little bit from current
master version. Is it possible to send PR back-porting to branches
representing those releases, or is the recommended practice to clone
open-embedded and provide the recipes there on my own?

Thank you, best regards,

Stanislav Angelovic.