fix: gorelaser-fips docker login setup

Part of https://gitlab.com/gitlab-com/gl-infra/gitlab-dedicated/team/-/issues/1312

It turns out that the `entrypoint.sh` in the cross compile version of the goreleaser
docker image is completely different from the original. It expects a json in a custom
format to run `docker login` inside the container.

Rather than try and construct the json it expects from CI variables and pass that in,
we will instead run `docker login` in the CI job and then just mount the docker auth
file into the container itself.

goreleaser.yml

@@ -85,10 +85,12 @@ goreleaser-fips:
     ----------------------------------------------------------
     Running go-releaser in fips mode
     EOD
+    echo "$CI_REGISTRY_PASSWORD" | docker login "$CI_REGISTRY" -u "$CI_REGISTRY_USER" --password-stdin
     docker run --rm --privileged \
       -v $PWD:$PWD \
       -w $PWD \
       -v /var/run/docker.sock:/var/run/docker.sock \
+      -v $HOME/.docker/config.json:/root/.docker/config.json \
       -e DOCKER_USERNAME -e DOCKER_PASSWORD -e DOCKER_REGISTRY  \
       -e GITLAB_TOKEN -e CI_REGISTRY_IMAGE \
       -e CI_SERVER_URL \