prepare changelog for release v1.73.0

Author: rolandwalker

changelog.md

@@ -1,11 +1,12 @@
-Upcoming (TBD)
+1.73.0 (2026/05/27)
 ==============
 
 Features
 ---------
 * Update `cli_helpers` to v2.15.0 for `mysql_heavy` table format.
 * Add `sqlglot` and `pygments` to `--checkup` output.
 
+
 Bug Fixes
 ---------
 * Respect `history_file` setting in the `[main]` section of `~/.myclirc`.