Improve concurrency of message sending

Issue-ID: NONRTRIC-635
Signed-off-by: elinuxhenrik <henrik.b.andersson@est.tech>
Change-Id: I414740a918eb65abae94c91990ff39a3cfc7bd22
diff --git a/dmaap-mediator-producer/Dockerfile b/dmaap-mediator-producer/Dockerfile
index bc09fdc..1c7f45c 100644
--- a/dmaap-mediator-producer/Dockerfile
+++ b/dmaap-mediator-producer/Dockerfile
@@ -20,7 +20,7 @@
 ##
 ## Build
 ##
-FROM golang:1.17-bullseye AS build
+FROM nexus3.o-ran-sc.org:10001/golang:1.17-bullseye AS build
 WORKDIR /app
 COPY go.mod .
 COPY go.sum .