Request: add clang-format-6.0
clang-format has moved on, the latest version is 6.0 and upcoming will
be 7.0 at some point.
the latest version on Alpine is 5.0, even in edge
is it possible to add clang-format-6.0?
it’s available at https://clang.llvm.org/
(from redmine: issue id 8793, created on 2018-04-12)