Remove Dev mode and make the release stable

Author: agentmilindu

snapcraft.yaml

@@ -4,7 +4,8 @@ summary: A Docker based task runner tool
 description: |
   Dunner is a task runner tool like Grunt but used Docker images like CircleCI do. | 
   You can define tasks and steps of the tasks in your `.dunner.yaml` file and then run these steps with `Dunner do taskname`
-confinement: devmode
+grade: stable
+confinement: strict
 base: core18
 
 parts:
@@ -18,4 +19,4 @@ parts:
 
 apps:
   dunner:
-    command: Dunner
+    command: bin/dunner