storage/src/lib.rs#119 fails for `--release`

https://github.com/Joystream/joystream/blob/b956002127ecff2c77321d149cc06af4f7afea12/runtime-modules/storage/src/lib.rs#L119

This step fails for
```
WASM_BUILD_TOOLCHAIN=nightly-2022-11-15 cargo build --release
...
Compiling pallet-storage v5.0.0 (/home/joystream/joystream/runtime-modules/storage)
error[E0554]: `#![feature]` may not be used on the stable release channel
--> runtime-modules/storage/src/lib.rs:119:12
|
119 | #![feature(step_trait)]
```

## Details

blame https://github.com/Joystream/joystream/commit/cde6219f97c1159d87f644427201f9df53ee7495

> Feature attributes are only allowed on the nightly release channel. Stable or beta compilers will not comply.
>
> Erroneous code example:
>
> #![feature(lang_items)] // error: `#![feature]` may not be used on the
> // stable release channel
>
> If you need the feature, make sure to use a nightly release of the compiler (but be warned that the feature may be removed or altered in
> the future).