fix broken link

BetterYTM.user.js

@@ -444,7 +444,7 @@ function addGeniusButton()
 
     const imgElem = document.createElement("img");
     imgElem.id = "betterytm-lyrics-img";
-    imgElem.src = "https://raw.githubusercontent.com/Sv443/BetterYTM/develop/resources/external/genius.png";
+    imgElem.src = "https://raw.githubusercontent.com/Sv443/BetterYTM/main/resources/external/genius.png";
 
     linkElem.appendChild(imgElem);