Fix broken URL (#27)

conda-forge/staged-recipes#21054 (review)

Author: maresb

setup.py

@@ -23,7 +23,7 @@
 DESCRIPTION = "Bayesian Additive Regression Trees for Probabilistic programming with PyMC"
 AUTHOR = "PyMC Developers"
 AUTHOR_EMAIL = "[email protected]"
-URL = "http://github.com/pymc-devs/pymc_bart"
+URL = "http://github.com/pymc-devs/pymc-bart"
 LICENSE = "Apache License, Version 2.0"
 
 classifiers = [