Remove "core: 8.x" from the .info.yml file

Hello Maintainers,
I have provided a patch for this issue.
Please review it.

Thanks!

-# core: 8.x
 package: Gallery Slider
 dependencies:
   - drupal:field

Actually, the content of the .info.yml file is the following.

name: Gallery slider
type: module
description: Gallery Slider jQuery plugin integration module.
# core: 8.x
package: Gallery Slider
dependencies:
  - drupal:field
  - drupal:image
core_version_requirement: ^8 || ^9

The correct change is either one or the other of the following:

• # core: 8.x is changed to core: 8.x
• core_version_requirement: ^8 || ^9 is changed to core_version_requirement: ^8.8 || ^9

@apaderno, I have updated the patch 3368493-2.patch or an MR !3 please review.