reverse_proxy: Configurable request headers on active health checks
reverse_proxy: Configurable request headers on active health checks

See https://caddy.community/t/health-check-user-agent/6309

abiosoft/caddy,abiosoft/caddy,mholt/caddy,l3dlp/caddy,l3dlp/caddy,mholt/caddy,l3dlp/caddy