fix matplotlib

Author: selmanozleyen

pyproject.toml

@@ -27,7 +27,6 @@ dependencies = [
     "torch_sparse",
     "torch_cluster",
     "torch_scatter",
-    "matplotlib==3.6",
     "squidpy",
     "scipy",
     "numpy",
@@ -57,6 +56,7 @@ doc = [
     "ipython",
     "sphinx-copybutton",
     "pandas",
+    "matplotlib>=3.6",
 ]
 test = [
     "pytest",