pip update is required otherwise the cuckoo installation fails

[RobertoD91]

After vagrant up i see:

Collecting setuptools (from jsonschema->pymisp==2.4.106->cuckoo)
  Using cached https://files.pythonhosted.org/packages/2f/8e/38259f4a44944a92068d5ff77230511a4c685604b47a81318f9e5cf2cc24/setuptools-49.2.0.zip
    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "setuptools/__init__.py", line 21, in <module>
        import setuptools.version
      File "setuptools/version.py", line 1, in <module>
        import pkg_resources
      File "pkg_resources/__init__.py", line 1380
        raise SyntaxError(e) from e
                                ^
    SyntaxError: invalid syntax
    
    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-cYz99c/setuptools/
You are using pip version 8.1.1, however version 20.1.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.

to fix add pip install --upgrade pip in bootstrap.sh before pip install -U supervisor