add filename parameter to upload method

Author: josiasmontag

README.md

@@ -93,7 +93,7 @@ const uploadTask = job.tasks.filter(task => task.name === 'upload-my-file')[0];
 
 const inputFile = fs.createReadStream('./file.pdf');
 
-await cloudConvert.tasks.upload(uploadTask, inputFile);
+await cloudConvert.tasks.upload(uploadTask, inputFile, 'file.pdf');
 ```
 
 

lib/TasksResource.ts

@@ -360,7 +360,7 @@ export default class TasksResource {
         await this.cloudConvert.axios.delete('tasks/' + id);
     }
 
-    async upload(task: Task | JobTask, stream: Stream): Promise<any> {
+    async upload(task: Task | JobTask, stream: Stream, filename: string | null = null): Promise<any> {
 
         if (task.operation !== 'import/upload') {
             throw new Error('The task operation is not import/upload');
@@ -376,7 +376,11 @@ export default class TasksResource {
             formData.append(parameter, task.result.form.parameters[parameter]);
         }
 
-        formData.append("file", stream);
+        let fileOptions = {};
+        if (filename) {
+            fileOptions = {filename: filename};
+        }
+        formData.append("file", stream, fileOptions);
 
         return await this.cloudConvert.axios.post(task.result.form.url, formData, {
             headers: {