fix: broken for_each on initial deploy

This is a pretty simple fix for the broken for_each error on initial deployment when using a load balancer (see #39 (closed)). However, it will cause any terraform configurations currently using load balancers in v5/v6 to destroy and recreate the resources when moving to use this patched version. With this in mind I'm proposing that we treat this as a breaking change and bump this module to v7, just to ensure users don't accidentally cause any downtime :-).

Closes #39 (closed)