Add missing dependency regions

Author: maxnoe

setup.py

@@ -3,7 +3,7 @@
 
 setup(
     name='irf',
-    version='0.2.0',
+    version='0.2.1',
     description='Functions to do instrument response functions for FACT',
     url='http://github.com/fact-project/irf',
     author='Kai Brügge, Maximilian Nöthe',
@@ -19,6 +19,7 @@
         'pyfact>=0.20.1',
         'uncertainties',
         'corsikaio',
+        'regions',
     ],
     entry_points={
         'console_scripts': [