Delete rebase.yml

Deleting rebase action for now, as this is not allowed in Apache owned repositories

.github/workflows/rebase.yml

@@ -1,19 +0,0 @@
-# https://github.com/marketplace/actions/automatic-rebase  (https://github.com/cirrus-actions/rebase)
-on:
-  issue_comment:
-    types: [created]
-name: Automatic Rebase
-jobs:
-  rebase:
-    name: Rebase
-    if: github.event.issue.pull_request != '' && contains(github.event.comment.body, '/rebase')
-    runs-on: ubuntu-latest
-    steps:
-    - uses: actions/checkout@v2
-      with:
-        token: ${{ secrets.GITHUB_TOKEN }}
-        fetch-depth: 0
-    - name: Automatic Rebase
-      uses: cirrus-actions/rebase@1.4
-      env:
-        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}