[CI]use comment based PR rebase

.github/workflows/rebase.yml

@@ -0,0 +1,19 @@
+name: Automatic Rebase
+on:
+  issue_comment:
+    types: [created]
+jobs:
+  rebase:
+    name: Rebase
+    if: github.event.issue.pull_request != '' && contains(github.event.comment.body, '/rebase')
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout the latest code
+        uses: actions/checkout@v2
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          fetch-depth: 0 # otherwise, you will fail to push refs to dest repo
+      - name: Automatic Rebase
+        uses: cirrus-actions/rebase@1.4
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/rebase_on_push.yml

@@ -1,13 +0,0 @@
-name: Rebase
-on:
-  push:
-    branches: [develop]
-jobs:
-  rebase:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: peter-evans/rebase@v1
-        with:
-          base: develop
-          repository: syl20bnr/spacemacs
-          token: ${{ secrets.GITHUB_TOKEN }}