scripts: Print names of missing migrations in compatibility check.

This will make it much easier to debug any situations where this
happens.

scripts/lib/check-database-compatibility.py

@@ -26,6 +26,9 @@ for key, migration in loader.disk_migrations.items():
 if not missing:
     sys.exit(0)
 
+for migration in missing:
+    print(f"Migration {migration} missing in new version.")
+
 current_version = parse_version_from(os.path.join(DEPLOYMENTS_DIR, "current"))
 logging.error(
     "This is not an upgrade -- the current deployment (version %s) "