Small improvements to Readme

[patrick91]

Added links to discord and pypi

[botberry]

Hi, thanks for contributing to Strawberry 🍓!

We noticed that this PR is missing a RELEASE.md file. We use that to automatically do releases here on GitHub and, most importantly, to PyPI!

So as soon as this PR is merged, a release will be made 🚀.

Here's an example of RELEASE.md:

Release type: patch

Description of the changes, ideally with some examples, if adding a new feature.

Release type can be one of patch, minor or major. We use semver,so make sure to pick the appropriate type. If in doubt feel free to ask :)

[codecov]

Codecov Report

Merging #418 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #418   +/-   ##
=======================================
  Coverage   96.12%   96.12%           
=======================================
  Files          52       52           
  Lines        1342     1342           
  Branches      208      208           
=======================================
  Hits         1290     1290           
  Misses         28       28           
  Partials       24       24