improve messaging around auth token env var

Author: pinzon

README.md

@@ -65,7 +65,7 @@ custom:
 ### Configuration via environment variables
 
 The following environment variables can be configured (taking precedence over the values in `serverless.yml`):
-* `LOCALSTACK_AUTH_TOKEN`: **Required.** Your LocalStack auth token for LocalStack Pro. Obtain one from [LocalStack](https://app.localstack.cloud/).
+* `LOCALSTACK_AUTH_TOKEN`: Your LocalStack auth token for LocalStack Pro. Obtain one from [LocalStack](https://app.localstack.cloud/).
 * `AWS_ENDPOINT_URL`: LocalStack endpoint URL to connect to (default: `http://localhost:4566`). This is the recommended configuration, and replaces the deprecated config options (`EDGE_PORT`/`LOCALSTACK_HOSTNAME`/`USE_SSL`) below.
 * `EDGE_PORT`: LocalStack edge port to connect to (deprecated; default: `4566`)
 * `LOCALSTACK_HOSTNAME`: LocalStack host name to connect to (deprecated; default: `localhost`)
@@ -210,7 +210,7 @@ custom:
 ```
 
 ## Change Log
-* v1.4.0: Use LocalStack Pro image (`localstack/localstack-pro`) by default, require `LOCALSTACK_AUTH_TOKEN`. Addition of `image` config var
+* v1.4.0: Use LocalStack Pro image (`localstack/localstack-pro`) by default. Addition of `image` config var to set a different image
 * v1.3.1: prevent the mounting of code if the Lambda uses an ECR Image
 * v1.3.0: add support for built-in Esbuild in Serverless Framework v4 #267
 * v1.2.1: Fix custom-resource bucket compatibility with serverless >3.39.0, continue improving support for `AWS_ENDPOINT_URL`