change Shapeshifter import path to match upstream change

Dockerfile

@@ -7,7 +7,7 @@ RUN apt-get -q update && env DEBIAN_FRONTEND=noninteractive apt-get install -y -
 # don't need to do bash tricks to keep the layers small, as this is a multi-stage build
 ENV GOPATH=/go
 WORKDIR $GOPATH
-RUN go get -u github.com/OperatorFoundation/shapeshifter-dispatcher/shapeshifter-dispatcher
+RUN go get -u github.com/OperatorFoundation/shapeshifter-dispatcher
 RUN strip $GOPATH/bin/shapeshifter-dispatcher
 RUN go get -u github.com/kumina/openvpn_exporter
 RUN strip $GOPATH/bin/openvpn_exporter