* +github.com/dduan/tre
a clone of unix tree(1) command written in rust
* remove tree from `provides`
tree usually refers to https://gitlab.com/OldManProgrammer/unix-tree
let's not confuse the users
* simplify tests
* update fixture
* simplify tests
because the sorting of tre output is non-stable and can't be forced, we need to get rid of verbatim fixture comparison in tests
