Replace octocat image png -> svg (SchemaStore#5329)

Author: Kissaki

src/css/site.css

@@ -161,6 +161,12 @@ header h1 a {
   /*width: 50%;*/
 }
 
+img.octocat {
+  background: light-dark(transparent, #333);
+  padding: 1em 0.5em;
+  border-radius: 20%;
+}
+
 footer {
   text-align: right;
   font-size: 80%;

src/img/octocat.png

@@ -1,4 +1,4 @@
-@{
+@{
 	Page.Title = "JSON Schema Store";
 	Page.Description = "JSON Schemas for common JSON file formats";
 	Layout = "~/_layout.cshtml";
@@ -130,7 +130,7 @@
 <article>
     <h3 id="contribute">Contribute</h3>
     <p>
-        <img src="/img/octocat.png" width="250" height="208" alt="Hosted on GitHub" class="left" />
+        <img src="/img/octocat.svg" width="250" height="208" alt="Hosted on GitHub" class="left octocat" />
         The goal of this API is to include schemas for all commonly
         known JSON file formats. To do that we encourage contributions in terms of new schemas,
         modifications and test files.