BUG: updated SSJ failure test

Updated the failure message for the DMSP SSJ function.

ocbpy/tests/test_dmsp_ssj_files.py

@@ -496,6 +496,6 @@ def test_import_failure(self):
         """ Test ssj_auroral_boundary import failure"""
 
         with self.assertRaisesRegex(ImportError,
-                                    'unable to load the DMSP SSJ module'):
+                                    'unable to load `zenodo_get` module'):
             from ocbpy.boundaries import dmsp_ssj_files  # NOQA F401
         return