Old old golang

422 > # Dependencies for BoringSSL and Quiche
423 > apt-get install -y golang

On Debian stretch the line above is installing some terribly old golang version (1.7 vs 1.13 latest) and messing my system slightly.

Is it possible to make that optional? Or perhaps better checking first if golang is already on the system (`go version`)

Of course I could comment that line out but I always forget. Silly me.