For openSUSE Leap 15.1 ARM run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:czanik:syslog-ng327/openSUSE_Leap_15.1_ARM/home:czanik:syslog-ng327.repo
zypper refresh
zypper install hiredis
For SLE 15 SP1 Backports run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:czanik:syslog-ng327/SLE_15_SP1_Backports/home:czanik:syslog-ng327.repo
zypper refresh
zypper install hiredis
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:czanik:syslog-ng327/15.5/home:czanik:syslog-ng327.repo
zypper refresh
zypper install hiredis