VOL-3978 - update to go 1.16.3

Change-Id: Ic58d4344cc98c8f4ce0a7b6a0bb538605750afe9
diff --git a/docker/Dockerfile.openolt b/docker/Dockerfile.openolt
index bc31eb3..36a0283 100644
--- a/docker/Dockerfile.openolt
+++ b/docker/Dockerfile.openolt
@@ -15,10 +15,10 @@
 # -------------
 # Build stage
 
-FROM --platform=linux/amd64 golang:1.13.8-alpine3.11 AS dev
+FROM --platform=linux/amd64 golang:1.16.3-alpine3.13 AS dev
 
 # Install required packages
-RUN apk add --no-cache build-base=0.5-r1
+RUN apk add --no-cache build-base=0.5-r2
 
 # Use Standard go build directory structure
 WORKDIR /go/src
@@ -52,7 +52,7 @@
 # -------------
 # Image creation stage
 
-FROM --platform=linux/amd64 gcr.io/distroless/static:nonroot as prod
+FROM --platform=linux/amd64 gcr.io/distroless/static:nonroot AS prod
 
 # Set the working directory
 WORKDIR /app