Force go to build with amd64 to cover Apple M1 chips (#209)

Author: kddejong

python/rpdk/go/templates/makebuild

@@ -4,4 +4,4 @@
 .PHONY: build
 build:
 	cfn generate
-	env GOOS=linux go build -ldflags="-s -w" -tags="$(TAGS)" -o bin/handler cmd/main.go
+	env GOARCH=amd64 GOOS=linux go build -ldflags="-s -w" -tags="$(TAGS)" -o bin/handler cmd/main.go