Starting from Terraform 0.12
you can use the Terraform CLI to generate a JSON representation of a given provider. Find the details and spec over here
Get the provider version you want and edit ./aws.tf.json accordingly.
Find available versions like this
curl -s https://registry.terraform.io/v1/providers/hashicorp/aws/versions | jq -r '.versions | .[] | .version'
The run the following
terraform init
terraform providers schema -json | jq > schema.json
Inspect the schema
cat schema.json