Update README.md

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: swoboda1337

README.md

@@ -13,7 +13,7 @@
 
 <a href="https://esphome.io/">
   <picture>
-    <source media="(prefers-color-scheme: dark)" srcset="https://media.esphome.io/logo/logo-text-on-dark.svg", alt="ESPHome Logo">
+    <source media="(prefers-color-scheme: dark)" srcset="https://media.esphome.io/logo/logo-text-on-dark.svg">
     <img src="https://media.esphome.io/logo/logo-text-on-light.svg" alt="ESPHome Logo">
   </picture>
 </a>