Pin Terraform version in managed instances to a max of 1.5.5

[GoodmanBen]

Current State

Due to uncertainty around the HashiCorp license change, when managed instances of Cloud Concierge are run, we should ensure that the Terraform version is capped to be a max of 1.5.5, the latest MPL version. Since we only run terraform init and terraform state update commands, this will not affect end functionality at all.

Desired State

While cloud-concierge does not compete with TFC/TFE (one cannot run terraform workflows using cloud-concierge), to add extra safety for our users of the managed instance we should cap the maximum version of Terraform useable within cloud-concierge to be 1.5.5