.github/workflows: Remove merge-stable from integration

Remove the merge-stable rule from integration.yaml to prevent
automatically merging patches from staging into stable. The
rationale is that right now that tests are still not comprehensive,
and it's still unclear how to correctly handle large feature sets
that consist of multiple PRs.

Signed-off-by: Michalis Pappas <michalis@unikraft.io>

Author: michpappas

.github/workflows/integration.yaml

@@ -94,23 +94,3 @@ jobs:
           exit 1;
         env:
           GITHUB_TOKEN: ${{ secrets.GH_CATALOG_PAT }}
-
-
-  merge-stable:
-    needs: [catalog-tests]
-    if: ${{ github.event_name == 'push' && github.ref == 'refs/heads/staging' && github.repository_owner == 'unikraft' }}
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          fetch-depth: 0
-          ref: staging
-
-      - name: Merge stable
-        run: |
-          set -e;
-
-          git pull origin stable;
-          git checkout --track origin/stable;
-          git rebase staging;
-          git push origin stable;