feat: Bump geokrety/geokrety-grafana in version-set to v1.0.21

Author: geokrety-bot

defaults/main/versionset.yml

@@ -30,7 +30,7 @@ geokrety_prometheus_image:
   docker_tag: 1.0.8
 geokrety_grafana_image:
   git_url: https://github.com/geokrety/geokrety-grafana
-  docker_tag: 1.0.20
+  docker_tag: 1.0.21
 geokrety_postgres_image:
   git_url: https://github.com/geokrety/geokrety-postgres
   docker_tag: 1.1.0