ERROR: Could not install packages due to an EnvironmentError: [Errno 13] Permission denied

[Rayman]

This doesn't occur with pip 8, but does with pip 19.1.1. We should probably add --user as argument to fix it.

edit: For ubuntu 18.04 we're still fine with the default pip version.

executing command [pip install -U marshmallow]
/home/user/.local/lib/python2.7/site-packages/pip/_vendor/requests/__init__.py:83: RequestsDependencyWarning: Old version of cryptography ([1, 2, 3]) may cause slowdown.
  warnings.warn(warning, RequestsDependencyWarning)
DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7.
Collecting marshmallow
  Using cached https://files.pythonhosted.org/packages/77/0b/ee5a4d0b7bc88bb3b59a25fb40e1811810c039f7faa1e87dcdcbcb1fdc33/marshmallow-2.19.5-py2.py3-none-any.whl
Installing collected packages: marshmallow
ERROR: Could not install packages due to an EnvironmentError: [Errno 13] Permission denied: '/usr/local/lib/python2.7/dist-packages/marshmallow-2.19.5.dist-info'
Consider using the `--user` option or check the permissions.

ERROR: the following rosdeps failed to install
  pip: command [pip install -U marshmallow] failed