Added LABELs to Dockerfile (#393)

Dockerfile

@@ -1,5 +1,4 @@
-FROM golang:1.17-alpine as basis
-LABEL maintainer="OpenSlides Team <info@openslides.com>"
+FROM golang:1.17-alpine as base
 WORKDIR /root/
 
 RUN apk add git
@@ -12,20 +11,20 @@ COPY internal internal
 COPY pkg pkg
 
 # Build service in seperate stage.
-FROM basis as builder
+FROM base as builder
 RUN CGO_ENABLED=0 go build ./cmd/autoupdate
 
 
 # Test build.
-FROM basis as testing
+FROM base as testing
 
 RUN apk add build-base
 
 CMD go vet ./... && go test ./...
 
 
 # Development build.
-FROM basis as development
+FROM base as development
 
 RUN ["go", "install", "github.com/githubnemo/CompileDaemon@latest"]
 EXPOSE 9012
@@ -38,6 +37,11 @@ CMD CompileDaemon -log-prefix=false -build="go build ./cmd/autoupdate" -command=
 # Productive build
 FROM scratch
 
+LABEL org.opencontainers.image.title="OpenSlides Autoupdate Service"
+LABEL org.opencontainers.image.description="The Autoupdate Service is a http endpoint where the clients can connect to get the current data and also updates."
+LABEL org.opencontainers.image.licenses="MIT"
+LABEL org.opencontainers.image.source="https://github.com/OpenSlides/openslides-autoupdate-service"
+
 COPY --from=builder /root/autoupdate .
 EXPOSE 9012
 ENV MESSAGING redis