chore(babelrc): drops node 0.12 support
chore(babelrc): drops node 0.12 support

Actually 1.x does not support 0.12 officially though it is likely to work on node 0.12. On 2.x we drop node 0.12 support since PostCSS 6.x drops node 0.12 support.

JLHwung/postcss-font-family-system-ui