Allow for the Jensen Shannon method to accept different kde classes

The purpose of this MR is to allow for the user to specify the which kde class they wish to use when working out the Jensen Shannon divergence.

tests/utils_test.py

@@ -571,7 +571,7 @@ def test_jensen_shannon_divergence():
     from scipy import stats
 
     samples = [
-        np.random.uniform(10, 5, 100),
+        np.random.uniform(5, 4, 100),
         np.random.uniform(5, 1, 100)
     ]
     x = np.linspace(np.min(samples), np.max(samples), 100)
@@ -583,7 +583,7 @@ def test_jensen_shannon_divergence():
     from pesummary.core.plots.bounded_1d_kde import Bounded_1d_kde
 
     _pesummary = utils.jension_shannon_divergence(
-        samples, decimal=9, kde=Bounded_1d_kde, xlow=2, xhigh=12
+        samples, decimal=9, kde=Bounded_1d_kde, xlow=4.5, xhigh=5.5
     )