[MNT] [Dependabot](deps): Update scikit-base requirement

Updates the requirements on [scikit-base](https://github.com/sktime/skbase) to permit the latest version.
- [Release notes](https://github.com/sktime/skbase/releases)
- [Commits](sktime/skbase@v0.11.0...v0.12.0)

---
updated-dependencies:
- dependency-name: scikit-base
  dependency-type: direct:production
...

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

pyproject.toml

@@ -12,7 +12,7 @@ sktime = ">=0.30.0"
 numpyro = "<0.16"
 optax = ">=0.2"
 graphviz = "^0.20.3"
-scikit-base = "^0.11.0"
+scikit-base = "^0.12.0"
 skpro = "^2.8.0"
 
 ipykernel = { version = ">=6.26.0,<7.0.0", optional = true }