opensuse: refresh repository before build

So that every packages are correctly updated

jami-packaging#123
Change-Id: Ifba60362e656b185fd403dc2055d306e96aadb80

docker/Dockerfile_opensuse-leap_15.3

 FROM opensuse/leap:15.3
 
+RUN zypper refresh
+
 RUN zypper --non-interactive install -y \
         dnf \
         dnf-command\(builddep\) \

docker/Dockerfile_opensuse-leap_15.4

 FROM opensuse/leap:15.4
 
+RUN zypper refresh
+
 RUN zypper --non-interactive install -y \
         dnf \
         dnf-command\(builddep\) \