autosemver dependency breaking compatibility with Python 3.5

[elWanderero]

flask-shell-bpython's setup requirement autosemver was recently upgraded to version 1.0.0. That version is no longer compatible with Python 3.5 or lower.

However that project does not specify required Python version, meaning that pip still thinks it is compatible with any Python version. So upon doing a fresh install of flask-shell-bpython with Python 3.5 I get a syntax error during install.

I have successfully worked around this problem with Python 3.5.2 by installing the last autosemver version before 1 (i.e autosemver 0.5.5) and with that version everything works fine.

Steps to reproduce:

1. Create a virtual environment with Python 3.5 (I use miniconda.)
2. Activate the environment and run pip install --no-cache-dir flask-shell-bpython