Pull Request resolves # .

• I read the Generative AI policy and my contribution is either not created with the help of AI or is compatible with the policy and GNU/GPL 2 or later.

Summary of Changes

This pull request (PR) updates the "CONTRIBUTING.md" doc to the default branch switch after 6.2.0 stable:

• A hint about 5.4 being in security only support mode is added like we had it in 5.2 for 4.4.
• The branch for the current 6.x version is switched from 6.1-dev to 6.2-dev, and the branch for the next minor 6.x version is switched from 6.2-dev to 6.3-dev.

It is a follow up to PR #48675 which made the changes for the "README.md" file.

Testing Instructions

Code review.

Actual result BEFORE applying this Pull Request

"CONTRIBUTING.md" is outdated regarding the 6.x-dev branches and doesn't mention 5.4 security only support mode.

Expected result AFTER applying this Pull Request

"CONTRIBUTING.md" is up to date regarding the 6.x-dev branches and mentions 5.4 security only support mode.

Link to documentations

Please select:

• Documentation link for guide.joomla.org:

• No documentation changes for guide.joomla.org needed

• Pull Request link for manual.joomla.org:

• No documentation changes for manual.joomla.org needed