Update sles container dockerfile

packaging/suse/Dockerfile

@@ -10,13 +10,15 @@ ADD wanda.tar.gz premium-checks.tar.gz* /build/
 RUN mv /build/priv/catalog/* /build/wanda/priv/catalog || true && rm -fr /build/priv/
 # Workaround for https://github.com/openSUSE/obs-build/issues/487
 RUN zypper --non-interactive in sles-release
-RUN zypper -n in elixir elixir-hex erlang-rebar3
+RUN zypper -n in git-core elixir elixir-hex erlang-rebar3
 WORKDIR /build/wanda/
 ENV LANG en_US.UTF-8
 ENV LANGUAGE en_US:en
 ENV LC_ALL en_US.UTF-8
 ENV MIX_ENV=prod
 ENV MIX_HOME=/usr/bin
+ENV MIX_REBAR3=/usr/bin/rebar3
+ENV MIX_PATH=/usr/lib/elixir/lib/hex/ebin
 ENV VERSION=%%VERSION%%
 RUN mix phx.digest
 RUN mix release