Get julia_project from pypi instead of github url

setup.py

@@ -31,6 +31,6 @@ def readme():
       license='MIT',
       packages=['diffeqpy','diffeqpy.tests'],
       install_requires=['julia>=0.2',
-                        'julia_project @ git+https://github.com/jlapeyre/julia_project.git'],
+                        'julia_project>=0.0.21'],
       include_package_data=True,
       zip_safe=False)