[CI]remove rave wf

.github/workflows/rebase.yml

@@ -1,21 +0,0 @@
-on: 
-  issue_comment:
-    types: [created]
-name: Automatic Rebase
-jobs:
-  rebase:
-    name: Rebase
-    if: |
-      github.event.issue.pull_request != '' &&
-      contains(github.event.comment.body, '/rebase') &&
-      github.event.comment.author_association == 'COLLABORATOR'
-    runs-on: ubuntu-latest
-    steps:
-    - name: Checkout the latest code
-      uses: actions/checkout@v2
-      with:
-        fetch-depth: 0
-    - name: Automatic Rebase
-      uses: cirrus-actions/rebase@1.3.1
-      env:
-        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}