make url property of FileUploaderOptions optional

.github/workflows/on-publish.yml

@@ -51,8 +51,8 @@ jobs:
             dist
           key: dist-${{ github.run_id }}
       - run: |
-          npx nx run ng2-file-upload:build --prod
+          npx nx run ng2-file-upload:build --configuration production
-          npx nx run ng2-file-upload-demo:build
+          npx nx run ng2-file-upload-demo:build --configuration production
 
   # update release notes in github
   update_release_draft:

libs/ng2-file-upload/file-upload/file-uploader.class.ts

@@ -31,7 +31,7 @@ export interface FileUploaderOptions {
   maxFileSize?: number;
   queueLimit?: number;
   removeAfterUpload?: boolean;
-  url: string;
+  url?: string;
   disableMultipart?: boolean;
   itemAlias?: string;
   authTokenHeader?: string;