code: func (c *Client) FormationUpdate(appIdentity string, formationIdentity string, options *FormationUpdateOpts) (*Formation, error) {
  	var formationRes Formation
  	return &formationRes, c.Patch(&formationRes, "/apps/"+appIdentity+"/formation/"+formationIdentity, options)
  }
docs: // Update process type
  //
  // appIdentity is the unique identifier of the Formation's App.
  // formationIdentity is the unique identifier of the Formation. options is the
  // struct of optional parameters for this action.