fix(jwk retrieval): Fixing promise anti-pattern

Not wrapping a promise in a promise

lib/auth0verification.js

@@ -36,8 +36,7 @@ const getExcludedRoutes = function (configuredExclusions) {
 };
 
 const getAuthPublicKey = function (jwksUrl, cache, kid) {
-  return new Promise((resolve, reject) => {
-    cache.get(`kid${kid}`).then(function (data) {
+    return cache.get(`kid${kid}`).then(function (data) {
       if (!data) {
         var client = jwksClient({
           cache: true,
@@ -46,20 +45,19 @@ const getAuthPublicKey = function (jwksUrl, cache, kid) {
         });
         client.getSigningKey(kid, (err, key) => {
           if (err) {
-            reject(err);
+            return err;
           } else {
             var signingKey = key.publicKey || key.rsaPublicKey;
             var encodedValue = new Buffer(signingKey).toString("base64");
             cache.set(`kid${kid}`, encodedValue, 36000).then(() => {
-              resolve(new Buffer(signingKey));
+              return new Buffer(signingKey);
             });
           }
         });
       } else {
-        resolve(new Buffer(data, "base64"));
+        return new Buffer(data, "base64");
       }
     });
-  });
 };
 
 // secures the application with auth0, by implementing checks against