Bump version to 0.3.1 in manifest.json

Author: sayurin

custom_components/echonet_lite/manifest.json

@@ -12,5 +12,5 @@
   "quality_scale": "bronze",
   "requirements": ["pyhems==0.3.0"],
   "single_config_entry": true,
-  "version": "0.3.0"
+  "version": "0.3.1"
 }