docs(readme): add actuated linkback

Thanks again for the sponsorship @alexellis

ref: https://docs.actuated.dev/faq/#is-there-a-sponsored-subscription-for-open-source-projects

README.md

@@ -16,6 +16,7 @@
   <a href="https://discord.gg/Fq8bJSKPHh"><img src="https://img.shields.io/discord/954121165239115808" /></a>
   <a rel="me" href="https://hachyderm.io/@atuin"><img src="https://img.shields.io/mastodon/follow/109944632283122560?domain=https%3A%2F%2Fhachyderm.io&style=social"/></a>
   <a href="https://twitter.com/atuinsh"><img src="https://img.shields.io/twitter/follow/atuinsh?style=social" /></a>
+  <a href="https://actuated.dev/"><img alt="Arm CI sponsored by Actuated" src="https://docs.actuated.dev/images/actuated-badge.png" width="120px"></img></a>
 </p>