code: public FileUpload uploadFile(Object projectIdOrPath, File fileToUpload, String mediaType) throws GitLabApiException {
          Response response = upload(Response.Status.CREATED, "file", fileToUpload, mediaType, "projects", getProjectIdOrPath(projectIdOrPath), "uploads");
          return (response.readEntity(FileUpload.class));
      }
docs: Uploads a file to the specified project to be used in an issue or merge request description, or a comment.
  
  <pre><code>POST /projects/:id/uploads</code></pre>
  
  @param projectIdOrPath projectIdOrPath the project in the form of an Integer(ID), String(path), or Project instance, required
  @param fileToUpload the File instance of the file to upload, required
  @param mediaType the media type of the file to upload, optional
  @return a FileUpload instance with information on the just uploaded file
  @throws GitLabApiException if any exception occurs