Для openSUSE Leap 15.6 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/home:Ledest:erlang:26/openSUSE_Leap_15.6/home:Ledest:erlang:26.repo
zypper refresh
zypper install myproto
Для openSUSE Leap 15.5 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/home:Ledest:erlang:26/openSUSE_Leap_15.5/home:Ledest:erlang:26.repo
zypper refresh
zypper install myproto
Для openSUSE Leap 15.4 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/home:Ledest:erlang:26/openSUSE_Leap_15.4/home:Ledest:erlang:26.repo
zypper refresh
zypper install myproto