Add GH actions workflow to test on Cubed

.github/workflows/cubed.yml

@@ -0,0 +1,33 @@
+name: Cubed
+
+on:
+  push:
+  pull_request:
+  # manual trigger
+  workflow_dispatch:
+
+jobs:
+  build:
+    # This workflow only runs on the origin org
+    # if: github.repository_owner == 'sgkit-dev'
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ["3.11"]
+
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v5
+      with:
+        python-version: ${{ matrix.python-version }}
+
+    - name: Install deps and sgkit
+      run: |
+        python -m pip install --upgrade pip
+        python -m pip install -r requirements.txt -r requirements-dev.txt
+        python -m pip install -U git+https://github.com/cubed-dev/cubed.git -U git+https://github.com/cubed-dev/cubed-xarray.git -U git+https://github.com/pydata/xarray.git
+
+    - name: Test with pytest
+      run: |
+        pytest -v sgkit/tests/test_aggregation.py -k "test_count_call_alleles" --use-cubed