Upgrade alpine to 3.12


Hi, we have trouble so setup Skygear with Alpine 3.12 since the version 1.7.2 (or 1.7.3 as well) are built with Alpine 3.8 (the problem is the libzmq which is 4.3.3 in Alpine and 4.2.1 in skygear). Could you provide a build with the upgraded Alpine version?

Thanks and regards