Setup DCO workflow (#4944)

* Setup DCO workflow

because of the dcoapp's hosting side issue, add a workflow to check DCO

Signed-off-by: Shinnosuke Sawada <shin@warashi.dev>

* Remove unallowed actions from DCO workflow

Signed-off-by: Shinnosuke Sawada <shin@warashi.dev>

* Change name of DCO workflow to specify this is a workaround

Signed-off-by: Shinnosuke Sawada <shin@warashi.dev>

---------

Signed-off-by: Shinnosuke Sawada <shin@warashi.dev>

.github/workflows/dco.yaml

@@ -0,0 +1,19 @@
+name: DCO-workaround
+on:
+  pull_request:
+  push:
+    branches:
+      - master
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Check DCO
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          # We use python3 without installing it because ubuntu-latest has preinstalled python3, and we remove this workflow after the recovery of the checker we use as usual.
+          pip3 install -U dco-check
+          dco-check --verbose --exclude-pattern 'dependabot\[bot\]@users\.noreply\.github\.com'