Fix colab URL (#1981)

docs/source/_templates/layout.html

@@ -64,7 +64,7 @@
 	      var githubLink = "https://github.com/pytorch/audio/blob/main/examples/gallery/"  + tutorialUrlArray.join("/") + ".py",
 		  notebookLink = $(".reference.download")[1].href,
 		  notebookDownloadPath = notebookLink.split('_downloads')[1],
-		  colabLink = "https://colab.research.google.com/github/pytorch/audio/blob/gh-pages/_downloads" + notebookDownloadPath;
+		  colabLink = "https://colab.research.google.com/github/pytorch/audio/blob/gh-pages/main/_downloads" + notebookDownloadPath;
 
 	      $(".pytorch-call-to-action-links a[data-response='Run in Google Colab']").attr("href", colabLink);
 	      $(".pytorch-call-to-action-links a[data-response='View on Github']").attr("href", githubLink);