Merge pull request #20 from jwtk/fix-package-version

Fix package license to be a valid SPDX identifier

Author: robertjd

package.json

@@ -17,7 +17,7 @@
     "jwt"
   ],
   "author": "Stormpath, Inc.",
-  "license": "Apache 2.0",
+  "license": "Apache-2.0",
   "bugs": {
     "url": "https://github.com/jwtk/njwt/issues"
   },