Makes the "generate provider" section unique
Important to know: If you use
```
generate "provider" {
```
in your local terragrunt.hcl, this overrides the one from
terragrunt.hcl.
HOWEVER, you may not notice right away, because if you've previously run
a `terragrunt init`, the generate clause from the root terragrunt.hcl
will be executed and the `provider.tf` it generated will remain present.
It's not until you reset the cache (`rm -rf .terragrunt-cache`) that the
file will be gone and won't be regenerated.
Fred Damstra