Update Leo color to latest brand colors. (#7425)

* Add Linguist support

* Add cached license file

* Update Leo color

Author: d0cd

lib/linguist/languages.yml

@@ -3967,7 +3967,7 @@ Lean 4:
   language_id: 455147478
 Leo:
   type: programming
-  color: "#6814EC"
+  color: "#C4FFC2"
   extensions:
   - ".leo"
   tm_scope: source.leo