Fix license name typo (#19)

Author: yakhinvadim

package.json

@@ -33,7 +33,7 @@
     "url": "git+https://github.com/elastic/app-search-javascript.git"
   },
   "author": "Elastic",
-  "license": "Apache 2.0",
+  "license": "Apache-2.0",
   "bugs": {
     "url": "https://github.com/elastic/app-search-javascript/issues"
   },