For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/Application:ERP:GNUHealth:4.4/openSUSE_Tumbleweed/Application:ERP:GNUHealth:4.4.repo
zypper refresh
zypper install trytond_stock_supply
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/Application:ERP:GNUHealth:4.4/15.6/Application:ERP:GNUHealth:4.4.repo
zypper refresh
zypper install trytond_stock_supply
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/Application:ERP:GNUHealth:4.4/15.5/Application:ERP:GNUHealth:4.4.repo
zypper refresh
zypper install trytond_stock_supply