constraint on sklearn version

requirements.txt

@@ -1,7 +1,7 @@
 numpy>=1.20.0
 pandas>=1.3.5
 scipy>=1.4.1
-scikit-learn>=0.19.1
+scikit-learn>=0.19.1,<1.5.0
 anndata>=0.8.0
 loompy>=3.0.5
 matplotlib>=3.5.3,<3.9.0