Reference earlier Node versions in README

Author: jch254

README.md

@@ -11,3 +11,5 @@ See [serverless-node-dynamodb-api](https://github.com/jch254/serverless-node-dyn
 This image is based on node:18-alpine ([AWS Lambda uses Node v18.x](http://docs.aws.amazon.com/lambda/latest/dg/current-supported-versions.html)) and has the AWS CLI, Serverless v3.33.0 and Yarn installed.
 
 To deploy a Serverless service to AWS you will need to create an IAM user with the required permissions and set credentials. I'm setting credentials using [Bitbucket Pipelines environment variables](https://confluence.atlassian.com/bitbucket/environment-variables-in-bitbucket-pipelines-794502608.html); however setting credentials in Dockerfile is also possible.
+
+Use the [16.x](https://github.com/jch254/docker-node-serverless/tree/16.x) branch/tag for an image running Node v16 and the [14.x](https://github.com/jch254/docker-node-serverless/tree/14.x) branch/tag for an image running Node v14.