Avif compression not implemented in proxy mode

[BugFest]

Describe the bug
webp_server_go does not use AVIF compression when configured in proxy mode

To Reproduce

{
    "IMG_PATH": "http://my.backend.server",
    "EXHAUST_PATH": "",
    "ENABLE_AVIF": true,
    ...
}

Expected behavior
I expect to get AVIF compressed images when provide better compression than WebP

Screenshots and logs
n/a

Environment (please complete the following information):

• OS: Linux, MacOS
• version or branch: 0.6.0

Additional context
n/a

[BugFest]

Opened PR #194 to fix/implement this

[Nova Kwok]

Yeah, that's indeed a problem, and thank you for your PR!

[BugFest]

Hi @n0vad3v, I've updated my PR. Please review

[Nova Kwok]

PR merged, thanks for your contribution!