remove the autorebase workflow (#148)

.github/workflows/autorebase.yml

-# File managed by web3-bot. DO NOT EDIT.
-# See https://github.com/protocol/.github/ for details.
-
-# Allow PRs opened by web3-bot to be rebased by commenting "@web3-bot rebase" on the PR.
-
-on: 
-  issue_comment:
-    types: [ created ]
-    
-name: Automatic Rebase
-jobs:
-  rebase:
-    name: Rebase
-    if: github.event.issue.pull_request != '' && github.event.issue.user.login == 'web3-bot' && contains(github.event.comment.body, '@web3-bot rebase')
-    runs-on: ubuntu-latest
-    steps:
-    - name: Checkout the latest code
-      uses: actions/checkout@v2
-      with:
-        fetch-depth: 0
-        token: ${{ secrets.WEB3BOT_GITHUB_TOKEN }}
-    - name: Automatic Rebase
-      uses: cirrus-actions/rebase@7cea12ac34ab078fa37e87798d8986185afa7bf2 # v1.4
-      env:
-        GITHUB_TOKEN: ${{ secrets.WEB3BOT_GITHUB_TOKEN }}