update docs with kms key arn instead of origin

Author: DrewGregory

terraform/README.md

@@ -101,7 +101,7 @@ terraform destroy
 | `aws_region` | AWS region to deploy resources | `us-east-1` |
 | `function_name` | Name of the Lambda function | `decrypt-lambda` |
 | `stage_name` | API Gateway stage name | `prod` |
-| `cors_origin` | CORS origin for API Gateway | `https://app.joinformal.com` |
+| `kms_key_arn` | ARN for KMS key we're using to decrypt | `` |
 | `lambda_environment_variables` | Environment variables for Lambda | `{}` |
 | `log_retention_days` | CloudWatch log retention in days | `14` |