Support '8.x-1.x' on Gitlab CI

Quick follow-up on this issue:

Fixed all the points listed in the issue summary at #2 in merge request MR!43.

Except:

• Create new legacy compatible development branch: 1.0.x
• Create stable release (1.0.0) and also set recommended (maintained)

 
It's probably more convenient sticking with the current 8.x-1.x development branch for now and a stable release will be created after support for D11 is added.

Otherwise, at this point: all tests seem to be passing on the 8.x-1.x branch.

Therefore, the tests configurations on DrupalCI for the 8.x-1.x branch were removed:
https://www.drupal.org/node/246513/qa →

The only tests remaining are for the D7 branches of the module.

Feel free to let us know if you have any questions or concerns on any aspects of this ticket or the latest changes in general, we would surely be glad to help.
Thanks in advance!

Automatically closed - issue fixed for 2 weeks with no activity.