feature has been removed

[yangmiok]

Compiling paillier v0.3.0 (https://github.com/KZen-networks/rust-paillier?tag=v0.3.0#735c95ec)
Compiling publicsuffix v1.5.4
error[E0557]: feature has been removed
--> /root/.cargo/git/checkouts/rust-paillier-5e0399ff4bbd1793/735c95e/src/lib.rs:1:12
|
1 | #![feature(custom_attribute)]
| ^^^^^^^^^^^^^^^^ feature has been removed
|
= note: removed in favor of #![register_tool] and #![register_attr]

error: aborting due to previous error

For more information about this error, try rustc --explain E0557.
error: could not compile paillier.

To learn more, run the command again with --verbose.
warning: build failed, waiting for other jobs to finish...
error: build failed

[yangmiok]

why?