google_tag 8.x-1.5

NOTES
- This release requires Drupal 8.8 or 9.0.
- It may be necessary to apply the core patch in #3114467: 'Negate' form value for condition plugins should be cast to boolean in validation. if the GTM snippets are no longer added to the page. This applies if other modules defining condition plugins are used on the site.

Feature requests
#3243890 Make label and weight translatable in ContainerForm.
#3153033 Support a cache backend as the inline snippet source.
#3151318 Allow for other scripts adding items to the dataLayer.

Miscellaneous tasks
#3183472 drupalPostForm() with drupalGet() and submitForm().
#3259001 Use file_url_generator service if present.
Consolidate similar code in ContainerManager::getScriptAttachments().
Add more dependency injection to container manager class.
#3151677 Use assertDirectoryNotExists() helper routine.
Refactor the compact snippet code to a separate routine.