Enabled go modules (#228)

Author: teddy-codes

.sail/Dockerfile

@@ -8,8 +8,7 @@ RUN curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.34.0/install.sh | b
 
 LABEL project_root "~/go/src/go.coder.com"
 
-# Modules break much of Go's tooling.
-ENV GO111MODULE=off
+ENV GO111MODULE=on
 
 # Install the latest version of Hugo.
 RUN wget -O /tmp/hugo.deb https://github.com/gohugoio/hugo/releases/download/v0.55.4/hugo_extended_0.55.4_Linux-64bit.deb && \