Inconsistent logo between GitHub repo and documentation site

[guangy10]

🐛 Describe the bug

Our documentation site (https://pytorch.org/executorch/main/index.html) is still referencing the old et logo.

Versions

trunk

cc @mergennachin @byjlw

[guangy10]

@byjlw assign to you since you were working on #8126 where the new logo was introduced

[byjlw]

You're talking about this one?

[guangy10]

Yes

[dbort]

I just published the logo (PNG + SVG) to https://github.com/dbort/executorch-logos/blob/main/img/executorch-chip-logo-white.png under a BSD license compatible with ExecuTorch's

There's also a version with a transparent background in the same directory; that'll probably be better for the site.

I see that the website uses the old logo for its favicon, too. I don't know if this logo will look good that small: I can experiment with a smaller version