reno: Update master for unmaintained/2024.1

Update the 2024.1 release notes configuration to build from unmaintained/2024.1. Change-Id: Ia4fff2a8e0f9bb083423c2e5c7339a46aaccd271 Signed-off-by: OpenStack Release Bot <infra-root@openstack.org> Generated-By: openstack/project-config:roles/copy-release-tools-scripts/files/release-tools/change_reno_branch_to_unmaintained.sh

Author: openstackadmin

releasenotes/source/2024.1.rst

@@ -3,4 +3,4 @@
 ===========================
 
 .. release-notes::
- :branch: stable/2024.1
+ :branch: unmaintained/2024.1