Update dependency font-awesome to v5.15.3

Author: renovate-bot

public/index.html

@@ -12,7 +12,7 @@
 		<link rel="stylesheet" href="https://unpkg.com/primer@latest/build/build.css"/>
 		<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/github-markdown-css/4.0.0/github-markdown.min.css">
 		<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"/>
-		<link href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.13.0/css/all.min.css" rel="stylesheet">
+		<link href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.15.3/css/all.min.css" rel="stylesheet">
 		<link href="https://fonts.googleapis.com/icon?family=Material+Icons" rel="stylesheet">
 		<title>Note</title>
 	</head>