That file has 2 comments in it:
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
Why not listen to the people that made/maintain this file? ;-)
From the man page:
Normally the resolvconf program is run only by network interface con‐
figuration programs such as pppd(8) (for ppp interfaces); by DHCP
clients such as dhclient(8); by ifup(8) and ifdown; and by DNS caches
such as dnsmasq(8) (for the loopback interface). These programs obtain
nameserver information from some source and push it to resolvconf.
The administrator can run resolvconf from the command line to add or
delete nameserver information, but this is not normally necessary or
Please use the method described here: How do I add a DNS server via resolv.conf? (Randall Cook seems the easiest and works for servers too).