Update dockerfile to add TARGETARCH (#1097)

Signed-off-by: Varsha B <vab@redhat.com>

Author: varshab1210

Dockerfile

@@ -16,8 +16,9 @@ COPY controllers/ controllers/
 COPY common/ common/
 COPY version/ version/
 
-# Build
-RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -a -o manager ./cmd/main.go
+# Build - Use TARGETARCH to build for the correct architecture
+ARG TARGETARCH
+RUN CGO_ENABLED=0 GOOS=linux GOARCH=${TARGETARCH} go build -a -o manager ./cmd/main.go
 
 # Use distroless as minimal base image to package the manager binary
 # Refer to https://github.com/GoogleContainerTools/distroless for more details