self-assign (#1911)

.github/bot.md

@@ -28,4 +28,4 @@ Assign:
 When you participating in an issue area, and you want to assign to others
 to distribute this task or self-assign to give a solution. You can use the comment bellow.
 * Write the word `/assign githubname` in a comment, the robot will automatically assign to the corresponding person.
-  
+* Specially, write the word `/assign` in a comment, you can assgin this task to yourself.  

.github/workflows/issue-commands.yml

@@ -14,7 +14,7 @@ jobs:
         with:
           repository: "oam-dev/kubevela-github-actions"
           path: ./actions
-          ref: v0.3
+          ref: v0.4
       - name: Install Actions
         run: npm install --production --prefix ./actions
       - name: Run Commands