add version strings to the nightly builds of nats cli

Signed-off-by: R.I.Pienaar <rip@devco.net>

.goreleaser-nightly.yml

@@ -19,6 +19,8 @@ dockers:
     goarch: amd64
     skip_push: true
     dockerfile: docker/Dockerfile.nightly
+    build_flag_templates:
+      - '--build-arg=VERSION=nightly-{{ time "20060102" }}'
     image_templates:
       - synadia/nats-server:{{.Version}}
       - synadia/nats-server:nightly

docker/Dockerfile.nightly

@@ -1,11 +1,13 @@
 FROM golang:1.15-alpine AS builder
 
+ARG VERSION="nightly"
+
 RUN apk add --update git
 RUN mkdir -p src/github.com/nats-io && \
     cd src/github.com/nats-io/ && \
     git clone https://github.com/nats-io/natscli.git && \
     cd natscli/nats && \
-    go build -o /nats
+    go build -ldflags "-s -w -X main.version=${VERSION}" -o /nats
 
 RUN go get github.com/nats-io/nsc