* fix(opensuse): update to openSUSE Leap >= 15.4

Signed-off-by: Georg Pfuetzenreuter <mail@georg-pfuetzenreuter.net>

* feat(opensuse): optional openSUSE devel repository

All modern openSUSE releases (Leap 15.x, Tumbleweed) ship nginx in the
default repositories. The devel repository should not be used unless the
user knows what they are doing.

Signed-off-by: Georg Pfuetzenreuter <mail@georg-pfuetzenreuter.net>

* fix(opensuse): pkgrepo.absent TypeError

Repository can only be removed by name, other fields cause del_repo() to
fail.

Signed-off-by: Georg Pfuetzenreuter <mail@georg-pfuetzenreuter.net>

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Signed-off-by: Georg Pfuetzenreuter <mail@georg-pfuetzenreuter.net>