docs: update README.md to include responsive images for branding

Author: awu

README.md

@@ -1,4 +1,10 @@
-# Wundii\Data-Mapper-Symfony-Bundle
+<div style="text-align:center">
+  <picture>
+    <source media="(prefers-color-scheme: dark)" srcset="https://raw.githubusercontent.com/wundii/data-mapper/refs/heads/main/assets/data-mapper-dark.png">
+    <source media="(prefers-color-scheme: light)" srcset="https://raw.githubusercontent.com/wundii/data-mapper/refs/heads/main/assets/data-mapper-light.png">
+    <img src="https://raw.githubusercontent.com/wundii/data-mapper/refs/heads/main/assets/data-mapper-light.png" alt="wundii/data-mapper-symfony-bundle" style="width: 100%; max-width: 600px; height: auto;">
+  </picture>
+</div>
 
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