Add grey border around color-block

Fixes #3184

netbox/project-static/css/base.css

@@ -559,6 +559,7 @@ table.report th a {
 .color-block {
     display: block;
     width: 80px;
+    border: 1px solid grey;
 }
 .text-nowrap {
     white-space: nowrap;