Update microfft requirement from ~0.5.1 to ~0.6.0

Updates the requirements on [microfft](https://gitlab.com/teskje/microfft-rs) to permit the latest version.
- [Changelog](https://gitlab.com/teskje/microfft-rs/blob/master/CHANGELOG.md)
- [Commits](https://gitlab.com/teskje/microfft-rs/compare/v0.5.1...v0.6.0)

---
updated-dependencies:
- dependency-name: microfft
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Cargo.toml

@@ -28,7 +28,7 @@ harness = false
 [dependencies]
 float-cmp = "~0.10.0"
 libm = "~0.2.7"
-microfft = { version = "~0.5.1", features = ["size-16384"] }
+microfft = { version = "~0.6.0", features = ["size-16384"] }
 paste = "~1.0.14"
 
 [dev-dependencies]