int -> float type annotation for LRFinder (#6364)

Fixes #6363.

### Description

Correct type annotation for `end_lr`.

### Types of changes

- [x] Non-breaking change (fix or new feature that would not break
existing functionality).

Signed-off-by: Josh <josh.e.stein@gmail.com>

monai/optimizers/lr_finder.py

@@ -257,7 +257,7 @@ def range_test(
         image_extractor: Callable = default_image_extractor,
         label_extractor: Callable = default_label_extractor,
         start_lr: float | None = None,
-        end_lr: int = 10,
+        end_lr: float = 10.0,
         num_iter: int = 100,
         step_mode: str = "exp",
         smooth_f: float = 0.05,

tests/test_lr_finder.py

@@ -91,7 +91,7 @@ def test_lr_finder(self):
             pickle_module=pickle,
             pickle_protocol=4,
         )
-        lr_finder.range_test(train_loader, val_loader=train_loader, end_lr=10, num_iter=5)
+        lr_finder.range_test(train_loader, val_loader=train_loader, end_lr=10.0, num_iter=5)
         print(lr_finder.get_steepest_gradient(0, 0)[0])
 
         if has_matplotlib: