Update logo image source paths in README

Author: ReneWerner87

.github/README.md

@@ -1,8 +1,8 @@
 <h1 align="center">
   <a href="https://gofiber.io">
     <picture>
-      <source height="125" media="(prefers-color-scheme: dark)" srcset="https://raw.githubusercontent.com/gofiber/docs/master/static/img/v3/logo-dark.svg">
-      <img height="125" alt="Fiber" src="https://raw.githubusercontent.com/gofiber/docs/master/static/img/v3/logo.svg">
+      <source height="125" media="(prefers-color-scheme: dark)" srcset="https://raw.githubusercontent.com/gofiber/docs/master/static/img/logo-dark.svg">
+      <img height="125" alt="Fiber" src="https://raw.githubusercontent.com/gofiber/docs/master/static/img/logo.svg">
     </picture>
   </a>
   <br>