Bump strum from 0.20.0 to 0.21.0 (#195)

* Bump strum from 0.20.0 to 0.21.0

Bumps [strum](https://github.com/Peternator7/strum) from 0.20.0 to 0.21.0.
- [Release notes](https://github.com/Peternator7/strum/releases)
- [Changelog](https://github.com/Peternator7/strum/blob/master/CHANGELOG.md)
- [Commits](https://github.com/Peternator7/strum/commits)

---
updated-dependencies:
- dependency-name: strum
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

* use dervie feature for strum; clippy and deny housekeeping

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: adoerr <[email protected]>

primitives/beefy/tests/light_client/mod.rs

@@ -217,7 +217,7 @@ impl LightClient {
 		let mut valid = 0;
 		for (signature, public) in signatures.into_iter().zip(validator_set.1.iter()) {
 			match signature {
-				Some(signature) if signature.is_valid_for(&public) => {
+				Some(signature) if signature.is_valid_for(public) => {
 					valid += 1;
 				}
 				_ => {}