feat: 🎸 upgrade nginx image to 1.25.3
fixes #1961.

RELEASE NOTES are here: https://nginx.org/en/CHANGES.

The change we're interested in is:
> *) Change: improved detection of misbehaving clients when using
HTTP/2.
feat: 🎸 upgrade nginx image to 1.25.3: fixes #1961.

RELEASE NOTES are here: https://nginx.org/en/CHANGES.

The change we're interested in is:
> *) Change: improved detection of misbehaving clients when using
HTTP/2.