Move to Go 1.16 images

Verified visually.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

Author: alexellis

template/golang-http/Dockerfile

@@ -1,5 +1,5 @@
 FROM --platform=${TARGETPLATFORM:-linux/amd64} ghcr.io/openfaas/of-watchdog:0.8.4 as watchdog
-FROM --platform=${BUILDPLATFORM:-linux/amd64} golang:1.15-alpine3.13 as build
+FROM --platform=${BUILDPLATFORM:-linux/amd64} golang:1.16-alpine3.13 as build
 
 ARG TARGETPLATFORM
 ARG BUILDPLATFORM

template/golang-http/go.mod

@@ -1,6 +1,6 @@
 module handler
 
-go 1.15
+go 1.16
 
 replace handler/function => ./function
 

template/golang-http/template.yml

@@ -1,7 +1,7 @@
 language: golang-http
 fprocess: ./handler
 welcome_message: |
-  You have created a new function which uses Go 1.15.
+  You have created a new function which uses Go 1.16.
 
   To include third-party dependencies, use Go modules and use
   "--build-arg GO111MODULE=on" with faas-cli build or configure this  

template/golang-middleware/Dockerfile

@@ -1,5 +1,5 @@
 FROM --platform=${TARGETPLATFORM:-linux/amd64} ghcr.io/openfaas/of-watchdog:0.8.4 as watchdog
-FROM --platform=${BUILDPLATFORM:-linux/amd64} golang:1.15-alpine3.13 as build
+FROM --platform=${BUILDPLATFORM:-linux/amd64} golang:1.16-alpine3.13 as build
 
 ARG TARGETPLATFORM
 ARG BUILDPLATFORM

template/golang-middleware/go.mod

@@ -1,5 +1,5 @@
 module handler
 
-go 1.15
+go 1.16
 
 replace handler/function => ./function

template/golang-middleware/template.yml

@@ -1,7 +1,7 @@
 language: golang-middleware
 fprocess: ./handler
 welcome_message: |
-  You have created a new function which uses Go 1.15.
+  You have created a new function which uses Go 1.16.
 
   To include third-party dependencies, use Go modules and use
   "--build-arg GO111MODULE=on" with faas-cli build or configure this