[MNT] [Dependabot](deps): Update polars requirement

Updates the requirements on [polars](https://github.com/pola-rs/polars) to permit the latest version.
- [Release notes](https://github.com/pola-rs/polars/releases)
- [Commits](pola-rs/polars@py-0.0.1...py-1.15.0)

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

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

pyproject.toml

@@ -55,7 +55,7 @@ all_extras = [
     "mapie; python_version < '3.13'",
     "matplotlib>=3.3.2",
     "ngboost<0.6.0; python_version < '3.13'",
-    "polars<1.14.0",
+    "polars<1.16.0",
     "pyarrow<14.0.0; python_version < '3.12'",
     "pymc; python_version < '3.13'",
     "scikit-survival<0.24.0; python_version < '3.13'",