Update model_regularizer type

`model_regularizer` (a.k.a lambda) should be float, not integer

Author: kieranrcampbell

Diff for: starling/starling.py

@@ -46,7 +46,7 @@ def __init__(
         model_cell_size: bool = True,
         cell_size_col_name: str = "area",
         model_zplane_overlap: bool = True,
-        model_regularizer: int = 1,
+        model_regularizer: float = 1.0,
         learning_rate: float = 1e-3,
     ):
         super().__init__()