ci: add automatic-rebase.yaml

Signed-off-by: Kenji Miyake <[email protected]>

Author: Kenji Miyake

.github/workflows/automatic-rebase.yaml

@@ -0,0 +1,29 @@
+name: automatic-rebase
+
+on:
+  issue_comment:
+    types:
+      - created
+
+jobs:
+  automatic-rebase:
+    if: ${{ github.event.issue.pull_request != '' && contains(github.event.comment.body, '/rebase') }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Generate token
+        id: generate-token
+        uses: tibdex/github-app-token@v1
+        with:
+          app_id: ${{ secrets.APP_ID }}
+          private_key: ${{ secrets.PRIVATE_KEY }}
+
+      - name: Check out repository
+        uses: actions/checkout@v2
+        with:
+          token: ${{ steps.generate-token.outputs.token }}
+          fetch-depth: 0
+
+      - name: Automatic rebase
+        uses: cirrus-actions/[email protected]
+        env:
+          GITHUB_TOKEN: ${{ steps.generate-token.outputs.token }}