Route requirement '_access' must be a string

Expanded context of issue for all defined key / values.

But this is not true see https://www.drupal.org/docs/drupal-apis/routing-system/structure-of-routes →
e.g. '_maintenance_access' and '_disable_route_normalizer' are boolean and not a string.

@slasher13 -- looking into this further, I'm finding conflicting documentation on this so I've reached out for clarification.

No clarification yet, but in searching through projects that we support at work, found the following similar implementation for another contrib module:

ckeditor5_icons module: https://git.drupalcode.org/project/ckeditor5_icons/-/blob/1.x/src/Routin...

public function getRoutes() {
    return [
      'ckeditor5_icons.fontawesome6_metadata' => new Route(
        '/' . $this->service->getFontAwesomeMetadataPath('6'),
        [
          '_controller' => 'Drupal\ckeditor5_icons\Controller\MetadataController::getFontAwesome6MetadataResponse',
          '_format' => 'json',
          '_disable_route_normalizer' => 'TRUE',
        ],
        [
          '_csrf_token' => 'TRUE',
        ]
      ),
     ....
    ];

If no clarification is received, I'll revise the committed work to remove the single quotes from _maintenance_access, but will leave them in place for _disable_route_normalizer.

I hate inconsistencies ... drives my OCD insane :)

Final update: didn't really receive any guidance, but a discussion in Slack was helpful. I decided to evaluate the Redirect module, which is the only module I was able to locate that actually used this key value pair in code, and given that this is a configuration setting for routes, I'm going with that as my assumption for correctness.

Redirect sets the same value in the same context as a boolean and evaluates it as such, so boolean it is.

@slasher13, I pushed a correction.

Ported to 2.2.x.