www/caddy: Update to 2.6.3

Major changes:

• New trusted_proxies global option (within servers) can be used to specify trusted proxy IP ranges globally. This is important if relying on headers for client IP addresses.

• Proxied WebSocket connections are now logged with correct status code and "size" (bytes read + bytes written).

• The quic-go package has received significant optimizations, so HTTP/3 should be more efficient now.