Add add-to-project step & rename workflow assign-issue workflow file

We are updating the workflows to auto-add new issues & PR to actions/cache project board.

.github/workflows/issue-opened-workflow.yml

@@ -14,3 +14,9 @@ jobs:
     - name: add_assignees
       run: |
         curl -X POST -H "Accept: application/vnd.github+json" -H "Authorization: Bearer ${{ secrets.GITHUB_TOKEN}}" https://api.github.com/repos/${{github.repository}}/issues/${{ github.event.issue.number}}/assignees -d '{"assignees":["${{steps.oncall.outputs.CURRENT}}"]}'
+
+    - uses: actions/add-to-project@v0.4.0
+      name: Add to Project Board
+      with:
+        project-url: https://github.com/orgs/actions/projects/12                       
+        github-token: ${{ secrets.CACHE_BOARD_TOKEN }}