Upgrade to swagger 3.9.3

I changed the swagger-ui package to use the dist package as that
is the recomended package for projects that don't use a bundler
such as webpack

Author: paxnovem

package-lock.json

@@ -1,8 +1,8 @@
 {
   "name": "flask-apispec",
-  "version": "0.3.1",
+  "version": "0.4.2",
   "dependencies": {
-    "swagger-ui": "2.1.3"
+    "swagger-ui-dist": "3.9.3"
   },
   "repository": {
     "type": "git",