feat: lock terraform version to 1.4.6

[sanketnadkarni]

Changes as below:

• added steps to use tfenv to the README.md
• added .terraform-version which acts as a configuration file for tfenv
• added required_version in provider.tf to use terraform version 1.4.6 ; reference: https://developer.hashicorp.com/terraform/tutorials/configuration-language/versions#review-example-configuration
• update setup_keys.sh script

To Do:

• currently all the above changes are only made to the dev folder, same needs to be replicated to the other envs.

❯ terraform version
Terraform v1.7.0
on darwin_amd64
+ provider registry.terraform.io/cyrilgdn/postgresql v1.11.0
+ provider registry.terraform.io/hashicorp/random v3.6.0

Your version of Terraform is out of date! The latest version
is 1.7.4. You can update by downloading from https://www.terraform.io/downloads.html


# If incorrect version is used terraform init command will fail with below error: 
❯ terraform init -backend-config=backend-config.tfvars

Initializing the backend...
Initializing modules...
╷
│ Error: Unsupported Terraform Core version
│
│   on provider.tf line 11, in terraform:
│   11:   required_version = "~> 1.4.6"
│
│ This configuration does not support Terraform version 1.7.0. To proceed, either choose another supported Terraform version or update this version constraint. Version constraints are
│ normally set for good reason, so updating the constraint may lead to other errors or unexpected behavior.
╵




# .terraform-version file will not allow to use incorrect version as seen below
❯ tfenv use 1.7.0
Switching default version to v1.7.0
Default version file overridden by /gs/treetracker-infrastructure/database-grants/terraform/dev/.terraform-version, changing the default version has no effect
Default version (when not overridden by .terraform-version or TFENV_TERRAFORM_VERSION) is now: 1.7.0

[dadiorchen]

This pull request looks good for me, accept the comment I made about

[sanketnadkarni]

This pull request looks good for me, accept the comment I made about

Cool thanks for the review @dadiorchen , I have addressed your comments, if all looks good , I will go ahead with merging this one and create another one for the remaining environments.

[sanketnadkarni]

@dadiorchen could you approve the PR