add delete custom metadata field method

Author: bishosilwal

lib/imagekitio/client.rb

@@ -160,6 +160,10 @@ def update_custom_metadata_fields(id, label, schema)
       @file.update_custom_metadata(id, label, schema)
     end
 
+    def delete_custom_metadata_fields(id)
+      @file.delete_custom_metadata(id)
+    end
+
     def phash_distance(first, second)
       # Get hamming distance between two phash(image hash) to check
       # similarity between images

lib/imagekitio/file.rb

@@ -238,6 +238,11 @@ def update_custom_metadata(id, label, schema)
       @req_obj.request('patch', url, @req_obj.create_headers, payload)
     end
 
+    def delete_custom_metadata(id)
+      url = "#{constants.API_BASE_URL}/customMetadataFields/#{id}"
+      @req_obj.request('delete', url, @req_obj.create_headers)
+    end
+
     def validate_upload_options(options)
 
       #  Validates upload value, checks if params are valid,