chore: update extension background color, move away from Clark's brand color

Author: imorland

extensions/audit/composer.json

@@ -41,7 +41,7 @@
             "category": "feature",
             "icon": {
                 "name": "fas fa-book",
-                "backgroundColor": "#684ba6",
+                "backgroundColor": "#475569",
                 "color": "#fff"
             },
             "optional-dependencies": [