Release 0.6.3

Documentation: lego 5's commands beside lego 4's, and lego on a host
inside a split DNS (its propagation check and the ways round it).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -6,6 +6,8 @@ All notable changes to Jarl are documented here. The format follows
 
 ## [Unreleased]
 
+## [0.6.3] - 2026-10-21
+
 ### Added
 
 - A docs/acme.md section: lego on a host inside a split DNS fails its own