update license value in package.json (#5050)

Author: Dottenpixel

package.json

@@ -200,7 +200,7 @@
   "optionalDependencies": {
     "fsevents": "*"
   },
-  "license": "SEE LICENSE IN README.md",
+  "license": "BSD-3-Clause",
   "repository": {
     "type": "git",
     "url": "[email protected]:salesforce-ux/design-system.git"