chore: promote to dev

package.json

@@ -1,6 +1,6 @@
 {
     "name": "zigbee2mqtt",
-    "version": "2.9.0",
+    "version": "2.9.0-dev",
     "description": "Zigbee to MQTT bridge using Zigbee-herdsman",
     "main": "index.js",
     "types": "dist/types/api.d.ts",
@@ -99,4 +99,4 @@
     "optionalDependencies": {
         "unix-dgram": "^2.0.7"
     }
-}
+}