Add maps migration to changelog

CHANGELOG.md

@@ -19,7 +19,6 @@
 - New environment variables [LAYMAN_QGIS_HOST](doc/env-settings.md#LAYMAN_QGIS_HOST), [LAYMAN_QGIS_PORT](doc/env-settings.md#LAYMAN_QGIS_PORT), and [LAYMAN_QGIS_PATH](doc/env-settings.md#LAYMAN_QGIS_PATH).
 - [#154](https://github.com/jirik/layman/issues/154) For endpoints [POST Layers](doc/rest.md#post-layers) and [PATCH Layer](doc/rest.md#patch-layer), parameter *sld* is replaced by the new parameter *style* and marked as deprecated. In response to endpoints [GET Layer](doc/rest.md#get-layer) and [PATCH Layer](doc/rest.md#patch-layer), *sld* is replaced by the new *style* item and marked as deprecated.
 
-
 ## v1.9.1
  2021-01-18
 ### Upgrade requirements