prosody: add temporary workaround for JWT auth

The previous commit updated Prosody to 0.12 and lua to 5.4. This also
forced us to update luajwtjitsi to the latest version (3.0.0), and we
hadn't landed a necessary fix in time for the stable release, so pick
the right file by hand until the next release.

prosody/Dockerfile

@@ -48,6 +48,8 @@ RUN wget -qO /etc/apt/trusted.gpg.d/prosody.gpg https://prosody.im/files/prosody
     apt-dpkg-wrap apt-get -d install -y jitsi-meet-prosody && \
     dpkg -x /var/cache/apt/archives/jitsi-meet-prosody*.deb /tmp/pkg && \
     mv /tmp/pkg/usr/share/jitsi-meet/prosody-plugins /prosody-plugins && \
+    rm -f /prosody-plugins/token/util.lib.lua && \
+    wget -qO /prosody-plugins/token/util.lib.lua https://raw.githubusercontent.com/jitsi/jitsi-meet/46dd88c91b63988f516114daee65ff8995c74c56/resources/prosody-plugins/token/util.lib.lua && \
     apt-cleanup && \
     rm -rf /tmp/pkg /var/cache/apt && \
     rm -rf /etc/prosody && \