Fix dockerfile targetarch scope with docker (#128)

Author: OlivierCazade

Dockerfile

@@ -1,11 +1,13 @@
 # We do not use --platform feature to auto fill this ARG because of incompatibility between podman and docker
 ARG TARGETPLATFORM=linux/amd64
 ARG BUILDPLATFORM=linux/amd64
+ARG TARGETARCH=amd64
+
 # Build the manager binary
 FROM --platform=$BUILDPLATFORM docker.io/library/golang:1.19 as builder
 
+ARG TARGETARCH
 ARG TARGETPLATFORM
-ARG TARGETARCH=amd64
 ARG VERSION="unknown"
 
 WORKDIR /opt/app-root