bump semver to ^4.3.3

package.json

@@ -64,7 +64,7 @@
     "express": "^4.11.2",
     "glob": "^4.4.0",
     "morgan": "^1.5.1",
-    "semver": "^4.3.0",
+    "semver": "^4.3.3",
     "void-elements": "^2.0.1"
   },
   "main": "./src/bootlint.js",