README.md: add Encore as sponsor (#1282)

Author: eandre

README.md

@@ -17,6 +17,14 @@ business value.
 
 ## Sponsors
 
+<div>
+  <a href="https://encore.dev" style="display: inline-flex; align-items: center; gap: 10px">
+    <img src="https://user-images.githubusercontent.com/78424526/214602214-52e0483a-b5fc-4d4c-b03e-0b7b23e012df.svg" height="28px" alt="encore icon"></img>
+  <b>Encore – the platform for building Go-based cloud backends.</b>
+    </a>
+</div>
+<br/>
+
 Click [here](https://github.com/sponsors/peterbourgon) or Sponsor, above, for more information on sponsorship.
 
 ## Motivation