Add contributing section

[logankilpatrick]

This will help get new people involved

[zlatanvasovic]

Is https://github.com/JuliaLang/julia/blob/master/CONTRIBUTING.md content sufficient?

[logankilpatrick]

I envision that plus some of the core aspects of this: https://devguide.python.org

[ViralBShah]

Is this relevant for GSOD?

[HarshCasper]

Hello @logankilpatrick @ViralBShah

Thanks for making this Issue as good first issue. I would like to work on this by taking inspiration from the JuliaLang Contribution File including some pointers from the Python Dev Guide.

Kindly assign me this or give me a go ahead so that I can bring up a draft and get a review on the same before I make a PR 😄

[ViralBShah]

#1328 has some concrete ideas, and the CONTRIBUTING.md document is updated from time to time.