docs: add themed logo

Author: rgomezcasas

README.md

@@ -1,6 +1,10 @@
 <p align="center">
   <a href="https://codely.com">
-    <img alt="Codely logo" src="https://user-images.githubusercontent.com/10558907/170513882-a09eee57-7765-4ca4-b2dd-3c2e061fdad0.png" width="300px" height="92px"/>
+    <picture>
+      <source media="(prefers-color-scheme: dark)" srcset="https://codely.com/logo/codely_logo-dark.svg">
+      <source media="(prefers-color-scheme: light)" srcset="https://codely.com/logo/codely_logo-light.svg">
+      <img alt="Codely logo" src="https://codely.com/logo/codely_logo.svg">
+    </picture>
   </a>
 </p>