fix(ci): docker build on x86_64 linux (#2051)

Currently, if `make build-docker` is executed on a Linux machine, `arch`
returns `x86_64` which is _not_ a valid `$GOARCH` value. Instead,
`amd64` should be used.

issue: none

Makefile

@@ -5,7 +5,7 @@ help:  ## Display this help message
 ###                                Docker                                 	###
 ###############################################################################
 
-ARCH := $(shell arch)
+ARCH := $(shell arch | sed 's/x86_64/amd64/')
 
 .PHONY: build-docker
 build-docker: ensure-go-releaser ## Builds the docker images using local arch.