chore: require Grafana 9 (#308)

Author: simPod

src/plugin.json

@@ -34,7 +34,7 @@
         "updated": "%TODAY%"
     },
     "dependencies": {
-        "grafanaDependency": ">=8.0.0",
+        "grafanaDependency": ">=9.0.0",
         "plugins": [ ]
     }
 }