update doc

[weixlu]

• README.md: after Use standardized (PEP 517) dependency syntax in pyproject.toml #114 , gpu dependency should be installed via --extras gpu
• Training.md: update SMB benchmark result on Run 426. smb_new.log
• Benchmark.md: That's what I want to discuss. Should we update it as well? And besides, I notice benchmark results are uploaded to release page, so maybe I should do the same this time. If so, then we need to think about how to give it a name for each run.

[liebharc]

Regarding, Benchmark.md and our release page. That's a good point. I think I want to keep things lean and not add too much process. In that sense I would occasionally update the numbers in Benchmark.md and upload new dbs to the release page, but not with every model update. It might be something to consider with every new minor version release. Training.md then remains the main spot to track results and this way we should also be able to spot regressions. And Benchmark.md and the DB releases have the purpose of giving people an idea what performance they can expect from homr.

Then it might however be good to add a note to Benchmark.md that these aren't necessarily the newest results.

[weixlu]

Sure, I also think we don't have to add too much process. Then this PR may seem fine.

[liebharc]

Yes, feel free to hit the merge button!