zypper ar https://download.opensuse.org/repositories/Application:/Geo/openSUSE_Leap_15.2/
zypper refresh
zypper install postgresql12-postgis postgresql12-contrib
# Configure access and so on, optionally create a DB to test this on, then …
psql -U postgres -c "CREATE EXTENSION postgis; CREATE EXTENSION postgis_raster;"
ERROR: could not load library "/usr/lib/postgresql12/lib64/postgis_raster-3.so": /usr/lib64/libgdal.so.28: undefined symbol: opj_encoder_set_extra_options