Start a 9.1.x branch for Varbase SEO to support Drupal ~10 and drop support for Drupal ~9

Problem/Motivation

Proposed resolution

• Start a 9.1.x branch with latest changes from the 9.0.x branch.
• Change drupal/core to ~10 in the .info.yml and composer.josn files in the 9.1.x branch
• Change drupal/core to ~9 in the .info.yml and composer.josn files in the 9.0.x branch
• Change drupal/core to ~10 in the .info.yml and composer.josn files in the 10.0.x branch to allow for a smooth update to latest stable Drupal 10 versions
• Drop support for Drupal ~9 on the 9.1.x branch
• Remove outdated and deprecated code for Drupal 9

Remaining tasks

• ✅ File an issue about this project
• ✅ Addition/Change/Update/Fix to this project
• ✅ Testing to ensure no regression
• ➖ Automated unit/functional testing coverage
• ➖ Developer Documentation support on feature change/addition
• ➖ User Guide Documentation support on feature change/addition
• ➖ UX/UI designer responsibilities
• ➖ Accessibility and Readability
• ✅ Code review from 1 Varbase core team member
• ✅ Full testing and approval
• ✅ Credit contributors
• ✅ Review with the product owner
• ✅ Update Release Notes and Update Helper on new feature change/addition
• ✅ Release varbase-9.0.17, varbase_seo-9.0.16, varbase-9.1.0, varbase_seo-9.1.0, varbase-10.0.0-rc1, varbase_seo-10.0.0

Varbase update type

• ✅ No Update
• ➖ Optional Update
• ➖ Forced Update
• ➖ Forced Update if Unchanged

User interface changes

• N/A

API changes

• N/A

Data model changes

• N/A

Release notes snippet

varbase_seo-9.1.0

• Issue #3403520: Started a 9.1.x branch for Varbase SEO to support Drupal ~10 and drop support for Drupal ~9

varbase_seo-9.0.16

• Issue #3403520: Changed drupal/core to ~9 in the .info.yml and composer.josn files in the 9.0.x branch

varbase_seo-10.0.0

• Issue #3403520: Changed drupal/core to ~10 in the .info.yml and composer.josn files in the 10.0.x branch to allow for a smooth update to latest stable Drupal 10 versions