Change DNS resolver from Google to Quad9

[mdPlusPlus]

lempstack/lemp-debian.sh

Line 143 in 4059121

resolver 8.8.8.8 8.8.4.4 valid=300s;

Change to resolver 9.9.9.9 149.112.112.112 valid=300s;.

https://www.quad9.net/service/service-addresses-and-features