Flask-simple-crypt

Minor changes

- Loosened Python version requirements from 3.9 to 3.7

Minor changes:

- Clarification on documentation

v.0.3.1
Mostly documentation:

- Updated README markdown
- Added instructions to install from PyPi
- Removed duplicate language around installing from source

What's Changed
* Create CODE_OF_CONDUCT.md by furritos in https://github.com/furritos/flask-simple-crypt/pull/1

New Contributors
* furritos made their first contribution in https://github.com/furritos/flask-simple-crypt/pull/1

**Full Changelog**: https://github.com/furritos/flask-simple-crypt/commits/v0.2.9