fix: add opengraph metadata

index.html

@@ -8,6 +8,12 @@
 	<meta name="description" content="tool for converting sketches to transparent lineart" />
 	<meta name="robots" content="index, follow" />
 
+	<meta property="og:type" content="website" />
+	<meta property="og:url" content="https://seansleblanc.itch.io/sketch-to-lineart" />
+	<meta property="og:title" content="sketch-to-lineart" />
+	<meta property="og:description" content="tool for converting sketches to transparent lineart" />
+	<meta property="og:image" content="https://raw.githubusercontent.com/seleb/sketch-to-lineart/main/cover.png" />
+
 	<link rel="icon" href="./src/icon.png" sizes="256x256" type="image/png" />
 
 	<script type="application/ld+json">