Update package name for msgpack

Author: vshlapakov

requirements.txt

@@ -1,2 +1,2 @@
 -r requirements-base.txt
-msgpack-python>=0.4.7
+msgpack>=0.6.1

setup.py

@@ -11,7 +11,7 @@
     version = f.read().decode('ascii').strip()
 
 is_pypy = '__pypy__' in sys.builtin_module_names
-mpack_required = 'msgpack-pypy>=0.0.2' if is_pypy else 'msgpack-python>=0.4.7'
+mpack_required = 'msgpack-pypy>=0.0.2' if is_pypy else 'msgpack>=0.6.1'
 
 setup(
     name='scrapinghub',