This should fix#435 for Helmfile v0.x releases since the next v0.150.0.
We introduce a new envvar to opt-in to the new YAML library, so that you can give it a shot before upgrading your Helmfile to v1. The same envvar can be used to opt-out of the new YAML library after you upgrade to Helmfile v1, giving you a more flexible migration story.
Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>