[24322] Bump version to v2.6.1

[emiliocuestaf]

Description

Bump version to v2.6.1

Contributor Checklist

• Commit messages follow the project guidelines.
• Tests that thoroughly check the new feature have been added/Regression tests checking the bug and its fix have been added; the added tests pass locally
• Changes are API compatible.
• Applicable backports have been included in the description.

Reviewer Checklist

• The PR has a milestone assigned.
• The title and description correctly express the PR's purpose.
• Check contributor checklist is correct.
• Check CI results: changes do not issue any warning.
• Check CI results: failing tests are unrelated with the changes.