Fix license syntax

Author: Kaelig Deloumeau-Prigent

package.json

@@ -14,7 +14,7 @@
     "salesforce"
   ],
   "author": "Salesforce",
-  "license": "CC BY-ND 4.0",
+  "license": "CC-BY-ND-4.0",
   "bugs": {
     "url": "https://github.com/salesforce-ux/design-system-ui-kit/issues"
   },