Update W3C logo to 2025 version

Update W3C logo to new one announced on 1 Oct 2025
https://www.w3.org/press-releases/2025/new-logo/

The logo is taken from the official logo page at https://www.w3.org/policies/logos/

Signed-off-by: Arthit Suriyawongkul <[email protected]>

Author: bact