build: add DEPR workflow automation

.github/workflows/add-depr-ticket-to-depr-board.yml

+# Run the workflow that adds new tickets that are either:
+# - labelled "DEPR"
+# - title starts with "[DEPR]"
+# - body starts with "Proposal Date" (this is the first template field)
+# to the org-wide DEPR project board
+
+name: Add newly created DEPR issues to the DEPR project board
+
+on:
+  issues:
+    types: [opened]
+
+jobs:
+  routeissue:
+    uses: openedx/.github/.github/workflows/add-depr-ticket-to-depr-board.yml@master
+    secrets:
+      GITHUB_APP_ID: ${{ secrets.GRAPHQL_AUTH_APP_ID }}
+      GITHUB_APP_PRIVATE_KEY: ${{ secrets.GRAPHQL_AUTH_APP_PEM }}
+      SLACK_BOT_TOKEN: ${{ secrets.SLACK_ISSUE_BOT_TOKEN }}
\ No newline at end of file