Update badge & links from Slack to Discord in README (#1612)
Update badge & links from Slack to Discord in README (#1612)

Co-authored-by: Michael Joseph <0556ac637a556e6bb405d02992f9bf002457a695@gmail.com>
Co-authored-by: Sorin Sbarnea <9cef7cb39dac69bd5a588dd1d139e9bb22437fa3@gmail.com>
audreyr/cookiecutter,audreyr/cookiecutter