correct js file name link in custom-cluster-theme

Signed-off-by: Langford, Chloe <[email protected]>

Author: greenred123

custom-cluster-theme/demo.details

@@ -3,7 +3,7 @@
  description: Cluster multiple markers and customize the theme
  resources:
    - http://heremaps.github.io/maps-api-for-javascript-examples/test-credentials.js
-   - http://heremaps.github.io/maps-api-for-javascript-examples/custom-cluster-theme/data/photo.js
+   - http://heremaps.github.io/maps-api-for-javascript-examples/custom-cluster-theme/data/photos.js
  normalize_css: no
  dtd: html 5
  wrap: d