Fix numpy 1.24 compatibility

Signed-off-by: Keith Battocchi <kebatt@microsoft.com>

Author: kbattocchi

econml/_ensemble/_ensemble.py

@@ -158,8 +158,8 @@ def _partition_estimators(n_estimators, n_jobs):
 
     # Partition estimators between jobs
     n_estimators_per_job = np.full(n_jobs, n_estimators // n_jobs,
-                                   dtype=np.int)
-    n_estimators_per_job[:n_estimators % n_jobs] += 1
+                                   dtype=int)
+    n_estimators_per_job[: n_estimators % n_jobs] += 1
     starts = np.cumsum(n_estimators_per_job)
 
     return n_jobs, n_estimators_per_job.tolist(), [0] + starts.tolist()