move dev dependencies out of requirements.txt

[jwa5426]

Moves any dependencies not needed for the actual package (i.e. for testing, code formatting, etc) into the dev requirements.

This pull request makes the following changes:

• Moves any dependencies not necessary for install_requires from requirements.txt into requirements-dev.txt
• Updates Pipfile and Pipfile.lock to reflect this ^
• Adds instruction to pip install from dev-dependencies.txt when running tests locally

It relates to the following issue #s:

• Fixes #27

cc @bhamail / @DarthHater

[sonatypecla[bot]]

Thanks for the contribution! Before we can merge this, we need @jwa5426 to sign the Sonatype Contributor License Agreement.

[jwa5426]

I’m a bit confused by the CI error, could someone point me in the right direction?

[jwa5426]

@bhamail Feel free to keep this open as long as you need, just commenting so this doesn't get forgotten.

[bhamail]

@jwa5426 Thanks for the PR!