feat(derp): optimize the derp chart template

images/tailscale-derp/Dockerfile

@@ -4,11 +4,6 @@ ARG VERSION=main
 
 RUN apk add git
 
-RUN apk add tailscale
-
 RUN go install tailscale.com/cmd/derper@${VERSION}
 
-COPY init.sh /init.sh
-RUN chmod +x /init.sh
-
-ENTRYPOINT [ "/init.sh" ]
+ENTRYPOINT [ "/go/bin/derper" ]