Remove Github DCO action since DCO runs via Github App now (#2317)

Signed-off-by: Vacha Shah <vachshah@amazon.com>

.github/workflows/dco.yml

@@ -1,18 +0,0 @@
-name: Developer Certificate of Origin Check
-
-on: [pull_request]
-
-jobs:
-  check:
-    runs-on: ubuntu-latest
-
-    steps:
-      - name: Get PR Commits
-        id: 'get-pr-commits'
-        uses: tim-actions/get-pr-commits@v1.1.0
-        with:
-          token: ${{ secrets.GITHUB_TOKEN }}
-      - name: DCO Check
-        uses: tim-actions/dco@v1.1.0
-        with:
-          commits: ${{ steps.get-pr-commits.outputs.commits }}