Update README with branch deprecation info

README.md

@@ -1,24 +1,14 @@
 # unb-libraries/docker-base  [![](https://github.com/unb-libraries/docker-base/workflows/build-test-deploy/badge.svg?branch=3.18.x)](https://github.com/unb-libraries/docker-base/actions?query=workflow%3Abuild-test-deploy) [![GitHub license](https://img.shields.io/github/license/unb-libraries/docker-base)](https://github.com/unb-libraries/lib.unb.ca/blob/prod/LICENSE) ![GitHub repo size](https://img.shields.io/github/repo-size/unb-libraries/docker-base?label=lean%20repo%20size)
 A lightweight extensible base docker image, suitable for development or production deployments.
 
-## Usage
-This image offers relatively no useful functionality on its own, but serves as the base of other images. For an example how we extend this image, please see [unb-libraries/docker-nginx](https://github.com/unb-libraries/docker-nginx).
-
-## Branches/Tags
-The only currently maintained branches are:
+## Warning!
+This branch is deprecated and will no longer receive updates. Applications currently using this branch should transition to one of the actively maintained branches. Below is a list of all maintained branches:
 
 |                  Tag                      | Alpine |
 |:-----------------------------------------:|--------|
 |  ghcr.io/unb-libraries/base:3.18.x        | 3.18   |
 |  ghcr.io/unb-libraries/base:3.17.x        | 3.17   |
 
-Other branches may exist for legacy purposes, but should not be used.
-
-## Author / Contributors
-This application was created at [![UNB Libraries](https://github.com/unb-libraries/assets/raw/master/unblibbadge.png "UNB Libraries")](https://lib.unb.ca) by the following humans:
-
-<a href="https://github.com/JacobSanford"><img src="https://avatars.githubusercontent.com/u/244894?v=3" title="Jacob Sanford" width="128" height="128"></a>
-
 ## License
 - As part of our 'open' ethos, UNB Libraries licenses its applications and workflows to be freely available to all whenever possible.
 - Consequently, the contents of this repository [unb-libraries/docker-base] are licensed under the [MIT License](http://opensource.org/licenses/mit-license.html). This license explicitly excludes: