code: public function updateProject(Project $project, $composerJson)
      {
  
          $response = $this->getResponse(
              'post',
              sprintf('v2/projects/%s', $project->getProjectKey()),
              array(),
              array('project_file' => $composerJson)
          );
  
          return $this->hydrator->hydrate($project, $response);
      }
docs: Update a project
  
  @param Project $project
  @param string $composerJson path
  @return array