docs: add deprecation banner to delete_head_branch action#10790

JulianMaurin wants to merge 1 commit intomainMergifyio/docs:mainfrom

devs/JulianMaurin/deprecate-queue-branch-merge-method/I86761e73de36c68ad13a723a17628acdd39bd221Mergifyio/docs:devs/JulianMaurin/deprecate-queue-branch-merge-method/I86761e73de36c68ad13a723a17628acdd39bd221Copy head branch name to clipboard