issue in build

[lokibyte]

getting issue while building.

error[E0554]: #![feature] may not be used on the stable release channel --> /Users/minacssybase/.cargo/registry/src/github.com-1ecc6299db9ec823/rls-span-0.4.0/src/lib.rs:12:1 | 12 | #![feature(proc_macro)] | ^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to previous error

error: Could not compile rls-span. warning: build failed, waiting for other jobs to finish... error: build failed

[scrogson]

@loki4u this library requires nightly at the moment.