[GSoC] Blog about weeks 9, 10

Hello everyone!

Over the last two weeks, I worked on handling mixed commit-graph chains and adding tests for the new premises - New Git can work with commit graph files without generation data chunk and New Git handle mixed commit-graph chains gracefully.

I apologize for the rather slow progress and missing out on the blog post for Week 9 - My college has re-commenced classes on 3rd August, and the transition to online learning has been chaotic and uncertain.

Thanks to Dr. Stolee, Dr. Narębski, and Taylor for their continued reviews and guidance.

https://abhishekkumar2718.github.io/gsoc/2020/08/09/gsoc-weeks-9-10.html

Thanks
- Abhishek