[Feature] upgrade to terraform 0.14

[sblack4]

This will be easy but requires deciding what to do with the dependency lock file.

• https://www.terraform.io/upgrade-guides/0-14.html
• https://github.com/hashicorp/terraform/tree/v0.14.8

Also, note that 0.15 is already in beta: https://github.com/hashicorp/terraform/blob/v0.15.0-beta1/CHANGELOG.md

[smiller171]

The dependency lock file should definitely be committed. It's like a package-lock.json in npm land and guarantees more predictable terraform runs, especially in automated systems.