changed GO version

[MikJagger]

Changed go version in installscript because of Amass install error:

from go1.13.4.linux-amd64.tar.gz to go1.16.linux-amd64.tar.gz

mkdir ExtTool && cd ExtTool
rm -rf go-*
wget https://dl.google.com/go/go1.16.linux-amd64.tar.gz
tar -xvf go1.16.linux-amd64.tar.gz
sudo mkdir /usr/lib/go-1.16
sudo cp -R go/* /usr/lib/go-1.16/
sudo rm /usr/bin/go
sudo ln -s /usr/lib/go-1.16/bin/go /usr/bin