max_buffer_size doesn't support go-humanize format

[bt90]

I'm toying a bit with OpenSpeedTest and tried to tune the max_buffer_size option of the reverse_proxy directive. According to the docs go-humanize formats should be supported:

speed.example.com {

        reverse_proxy http://localhost:8086 {
                buffer_requests
                max_buffer_size 50MiB
        }
}

Error: adapting config using caddyfile: parsing caddyfile tokens for 'reverse_proxy': /etc/caddy/Caddyfile:112 - Error during parsing: invalid size (bytes): 50MiB

[mholt]

Oops, thanks for the report. Fixed in 2a8c458. Please feel free to try it out!