Remove dependency on semver

Author: marco-c

package.json

@@ -35,7 +35,6 @@
     "http_ece": "^0.5.1",
     "jws": "^3.1.3",
     "minimist": "^1.2.0",
-    "semver": "^5.1.0",
     "urlsafe-base64": "^1.0.0"
   },
   "devDependencies": {