CI: call renderDockerfile even when needs_build is false
Discovered in https://dev.gitlab.org/gitlab/charts/components/images/-/jobs/7011329#L616
When the needs_build
returned true, renderDockerfile
was not called,
blocking push_if_master_or_stable_or_tag
from pushing the re-tagged
docker image with the git Tag version.
Move the renderDockerfile before needs_build, ensuring it is always rendered.