Build faster

Dockerfile

@@ -1,5 +1,6 @@
 # Build the manager binary
-FROM golang:1.18 as builder
+FROM --platform=$BUILDPLATFORM golang:1.18 as builder
+ARG TARGETARCH
 
 WORKDIR /workspace
 # Copy the Go Modules manifests
@@ -18,7 +19,7 @@ COPY installer/ installer/
 COPY common/ common/
 
 # Build
-RUN CGO_ENABLED=0 go build -a -o manager main.go
+RUN CGO_ENABLED=0 GOOS=linux GOARCH=$TARGETARCH go build -a -o manager main.go
 
 # Use distroless as minimal base image to package the manager binary
 # Refer to https://github.com/GoogleContainerTools/distroless for more details