fix: default value for grafana_plugins is empty array

CHANGELOG.md

@@ -3,8 +3,12 @@
 This project adheres to [Semantic Versioning](http://semver.org/).
 Which is based on [Keep A Changelog](http://keepachangelog.com/)
 
-## [Unreleased]
+## Unreleased
 
-## [1.0.0] - 2019-14-11
+### Fixed
+
+- default value for grafana_plugins is empty array
+
+## 1.0.0 - 2019-14-11
 
 - first version

defaults/main.yml

@@ -1,4 +1,4 @@
 ---
 grafana_config: {}
 grafana_ldap_config: {}
-grafana_plugins: {}
+grafana_plugins: []