Installation with pip not installing dependencies in v3.6.5

[patricklucas]

Describe the bug
It seems that v3.6.5, released two days ago, introduced a bug that results in some dependencies not being installed.

To Reproduce
Steps to reproduce the behavior:

1. Create a new virtualenv with virtualenv venv
2. Run pip install garmindb==3.6.5; it will succeed
3. Run ./venv/bin/garmindb_cli.sh -h
4. It will fail because fitfile is not installed. If you pip install fitfile, it will fail trying to import a different module.

Expected behavior
Installing via pip should install all required dependencies.

Additional context
Workaround is to install 3.6.4 instead with pip install garmindb==3.6.4.