Update go version

Dockerfile.build-env

@@ -1,5 +1,5 @@
 # Builder
-FROM golang:1.14 AS builder
+FROM golang:1.16 AS builder
 
 RUN apt-get update && apt-get install -y --no-install-recommends git dmsetup && apt-get clean
 

Dockerfile.multi-stage

@@ -1,6 +1,6 @@
 ARG REPO=library
 # Builder
-FROM golang:1.14 AS builder
+FROM golang:1.16 AS builder
 
 RUN apt-get update && apt-get install -y --no-install-recommends git dmsetup && apt-get clean