I don't understand why they're changing anything, I always looked up to GitHub's design as one of the best looking and consistent designs on the Internet. The new black bar looks very bland, out of place and definitely worse than previous one. This feels like a change for the sake of it...
I have been coding every day for several years until I've burnt out, now I'm slowly relearning how to enjoy life. It doesn't work for everyone; my mistake was to start treating unpaid hobby like serious work.