message: Use specific methods to add requirements
diff: @@ -955,10 +955,10 @@ fn build_requirements<'a, 'b: 'a>(s: &'a Summary, method: &'b Method)
  match *method {
  Method::Everything => {
  for key in s.features().keys() {
  - reqs.add_feature(key)?;
  + reqs.require_feature(key)?;
  }
  for dep in s.dependencies().iter().filter(|d| d.is_optional()) {
  - reqs.add_feature(dep.name())?;
  + reqs.require_dependency(dep.name());
  }
  }
  Method::Required { features: requested_features, .. } => {
  @@ -971,7 +971,7 @@ fn build_requirements<'a, 'b: 'a>(s: &'a Summary, method: &'b Method)
  Method::Everything |
  Method::Required { uses_default_features: true, .. } => {
  if s.features().get("default").is_some() {
  - reqs.add_feature("default")?;
  + reqs.require_feature("default")?;
  }
  }
  Method::Required { uses_default_features: false, .. } => {}
  