ImageProxyClient: Use create-hmac package instead of crypto

Author: fnesveda

package.json

@@ -41,6 +41,7 @@
     "cherow": "^1.6.9",
     "clone": "^2.1.1",
     "countries-list": "^2.5.1",
+    "create-hmac": "^1.1.7",
     "is-buffer": "^2.0.3",
     "marked": "^1.1.0",
     "match-all": "^1.2.6",

src/image_proxy_client.js

@@ -1,4 +1,4 @@
-import crypto from 'crypto';
+import createHmac from 'create-hmac';
 import querystring from 'querystring';
 
 /**
@@ -26,7 +26,7 @@ export default class ImageProxyClient {
     }
 
     _createDigest(string) {
-        const hmac = crypto.createHmac('sha1', this.hmacKey).update(string);
+        const hmac = createHmac('sha1', this.hmacKey).update(string);
         return hmac.digest('hex');
     }