Go Modules migration

.devcontainer/Dockerfile

@@ -1,5 +1,5 @@
 # Update the VARIANT arg in devcontainer.json to pick an Go version
-ARG VARIANT=1
+ARG VARIANT=1.14
 FROM golang:${VARIANT}
 
 # This Dockerfile adds a non-root user with sudo access. Update the “remoteUser” property in
@@ -27,17 +27,17 @@ RUN apt-get update \
     && rm -rf /var/lib/apt/lists/*
 
 # Install Go tools
+
+ENV GO111MODULE=on
+
 ARG GO_TOOLS_WITH_MODULES="\
     golang.org/x/tools/gopls \
     honnef.co/go/tools/... \
     golang.org/x/tools/cmd/gorename \
     golang.org/x/tools/cmd/goimports \
     golang.org/x/tools/cmd/guru \
-    golang.org/x/lint/golint \
-    github.com/mdempsky/gocode \
     github.com/cweill/gotests/... \
     github.com/haya14busa/goplay/cmd/goplay \
-    github.com/sqs/goreturns \
     github.com/josharian/impl \
     github.com/davidrjenni/reftools/cmd/fillstruct \
     github.com/uudashr/gopkgs/v2/cmd/gopkgs \
@@ -49,29 +49,13 @@ ARG GO_TOOLS_WITH_MODULES="\
     github.com/fatih/gomodifytags \
     github.com/mgechev/revive \
     github.com/go-delve/delve/cmd/dlv"
-RUN mkdir -p /tmp/gotools \
-    && cd /tmp/gotools \
-    && export GOPATH=/tmp/gotools \
-    # Go tools w/module support
-    && export GO111MODULE=on \
-    && (echo "${GO_TOOLS_WITH_MODULES}" | xargs -n 1 go get -x )2>&1 \
-    # gocode-gomod
-    && export GO111MODULE=auto \
-    && go get -x -d github.com/stamblerre/gocode 2>&1 \
-    && go build -o gocode-gomod github.com/stamblerre/gocode \
+
+RUN (echo "${GO_TOOLS_WITH_MODULES}" | xargs -n 1 go get )2>&1 \
     # golangci-lint
     && curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b /usr/local/bin 2>&1 \
-    # Move Go tools into path and clean up
-    && mv /tmp/gotools/bin/* /usr/local/bin/ \
-    && mv gocode-gomod /usr/local/bin/ \
-    && rm -rf /tmp/gotools
-
-ENV GO111MODULE=auto
-
 # [Optional] Uncomment the next line to use go get to install anything else you need
 # RUN go get -x <your-dependency-or-tool>
-
 # [Optional] Uncomment this section to install additional OS packages.
 # RUN apt-get update \
 #     && export DEBIAN_FRONTEND=noninteractive \
-#     && apt-get -y install --no-install-recommends <your-package-list-here>
+#     && apt-get -y install --no-install-recommends <your-package-list-here>