Add mim to extras_require in setup.py (open-mmlab#1655)

* Add mim to extras_require in setup.py

* fix typo

Author: zhouzaida

setup.py

@@ -195,6 +195,7 @@ def add_mim_extension():
             'tests': parse_requirements('requirements/tests.txt'),
             'build': parse_requirements('requirements/build.txt'),
             'optional': parse_requirements('requirements/optional.txt'),
+            'mim': parse_requirements('requirements/mminstall.txt'),
         },
         ext_modules=[],
         zip_safe=False)