Adds Pluralsight logo

Fix #450
Official brand color is gradient from #F15B2A to #EC008C
See their newsroom for more details (and resources)

_data/simple-icons.json

@@ -1000,6 +1000,11 @@
             "hex": "E5A00D",
             "source": "http://brand.plex.tv/d/qxmJ3odkK0fj/plex-style-guide"
         },
+        {
+            "title": "Pluralsight",
+            "hex": "F15B2A",
+            "source": "https://www.pluralsight.com/newsroom/brand-assets"
+        },
         {
             "title": "Plurk",
             "hex": "E9443D",

icons/pluralsight.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" version="1.2" baseProfile="tiny" viewBox="221.5 41.5 16 16"><path d="M231.98 42.67c-3.76-1.37-7.94.58-9.3 4.34-1.38 3.78.57 7.96 4.33 9.33s7.96-.58 9.33-4.34c1.37-3.78-.58-7.96-4.35-9.33zM229.5 57.5c-4.4 0-8-3.6-8-8s3.6-8 8-8 8 3.6 8 8-3.6 8-8 8"/><path d="M227.45 45.37v8.26l7.17-4.13-7.17-4.13zm.7 1.18l5.1 2.95-5.1 2.95v-5.9"/><path d="M225.8 46.27v6.46l5.6-3.23-5.6-3.23zm.7 1.2l3.54 2.03-3.55 2.04v-4.08"/></svg>