Update tc_tracks.py

float issue jenkins

Author: NicolasColombi

climada/hazard/tc_tracks.py

@@ -3029,7 +3029,7 @@ def compute_track_density(
 
     limit_ratio = 1.12 * 1.1  # record tc speed 112km/h -> 1.12°/h + 10% margin
 
-    if tc_track.data[0].time_step[0].item() > res / limit_ratio:
+    if float(tc_track.data[0].time_step[0].item()) > res / limit_ratio:
         warnings.warn(
             "The time step is too big for the current resolution. For the desired resolution, \n"
             f"apply a time step of {res/limit_ratio}h."