Add Discord link to README
Alert contributors to where on Discord they can reach out for questions and such
:target: https://github.com/PyCQA/bandit/blob/main/LICENSE
:alt: License
+.. image:: https://img.shields.io/discord/825463413634891776.svg
+ :target: https://discord.gg/qYxpadCgkx
+ :alt: Discord
+
A security linter from PyCQA
* Free software: Apache license
