Fix outdated `engineering blog` link in README

[inthree3]

Describe the bug
The link to the "engineering blog" post in README.md points to a post that no longer exists.

To Reproduce
Steps to reproduce the behavior:

1. Open READMD.md
2. Click on the linked text 'engineering blog'
3. The link returns a 404

Expected behavior
The link should point to a valid post describing this repo's history, motivation, what was excluded, etc.

Screenshots