Fix failures on macOS

Author: cajchristian

.github/workflows/tests.yml

@@ -13,7 +13,7 @@ jobs:
       matrix:
         os: 
           - ubuntu-latest
-          #- macos-latest  # see issue #271
+          - macos-latest
           - windows-latest
         python-version: 
           - "3.10"

tests/test_sample_simple_cur.py

@@ -1,7 +1,7 @@
 import unittest
 
 import numpy as np
-from sklearn.datasets import fetch_california_housing as load
+from sklearn.datasets import load_diabetes as load
 
 from skmatter.sample_selection import CUR, FPS