fix: ensure we install the golang for the correct architecture
fix: ensure we install the golang for the correct architecture

TARGETARCH is an automatic build-arg that docker injects - https://docs.docker.com/engine/reference/builder/#automatic-platform-args-in-the-global-scope - so this is safe to depend on.

dokku/dokku,dokku/dokku,dokku/dokku,dokku/dokku,dokku/dokku,dokku/dokku,dokku/dokku,dokku/dokku