Switch to `go install`

Dockerfile

@@ -12,7 +12,7 @@ ENV GOPATH=/go
 WORKDIR $GOPATH
 RUN git clone https://github.com/OperatorFoundation/shapeshifter-dispatcher /shapeshifter-dispatcher && cd /shapeshifter-dispatcher && /usr/lib/go-1.19/bin/go build
 RUN strip /shapeshifter-dispatcher/shapeshifter-dispatcher
-RUN /usr/lib/go-1.19/bin/go get -u github.com/kumina/openvpn_exporter
+RUN /usr/lib/go-1.19/bin/go install github.com/kumina/openvpn_exporter@latest
 RUN strip $GOPATH/bin/openvpn_exporter
 
 FROM registry.git.autistici.org/ai3/docker/s6-base