feat: Use 'method' arg for jax.numpy.percentile (#2522)

* Change the argument name in jax.numpy.percentile from 'interpolation' to 'method'.
  No change to the lower bounds on jax and jaxlib is required as 'method' already
  existed as an argument in jax v0.4.1. This just deprecates the use of 'interpolation'.
   - Avoids the following DeprecationWarning in jax v0.4.29+:

     > DeprecationWarning: The interpolation= argument to 'percentile' is deprecated.
     > Use 'method=' instead.
   - c.f. jax-ml/jax#21267

src/pyhf/tensor/jax_backend.py

@@ -321,7 +321,7 @@ def percentile(self, tensor_in, q, axis=None, interpolation="linear"):
 
         .. versionadded:: 0.7.0
         """
-        return jnp.percentile(tensor_in, q, axis=axis, interpolation=interpolation)
+        return jnp.percentile(tensor_in, q, axis=axis, method=interpolation)
 
     def stack(self, sequence, axis=0):
         return jnp.stack(sequence, axis=axis)