Add GitHub Actions workflow to run Dask tests

.coveragerc

@@ -4,6 +4,7 @@ omit =
     cubed/array_api/*
     cubed/extensions/*
     cubed/runtime/executors/beam.py
+    cubed/runtime/executors/dask.py
     cubed/runtime/executors/lithops.py
     cubed/runtime/executors/modal*.py
     cubed/vendor/*

.github/workflows/dask-tests.yml

@@ -0,0 +1,45 @@
+name: Dask tests
+
+on:
+  push:
+    branches:
+      - "main"
+  pull_request:
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: ["ubuntu-latest"]
+        python-version: ["3.9"]
+
+    steps:
+      - name: Checkout source
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      - name: Set up Python
+        uses: actions/setup-python@v3
+        with:
+          python-version: ${{ matrix.python-version }}
+          architecture: x64
+
+      - name: Setup Graphviz
+        uses: ts-graphviz/setup-graphviz@v1
+
+      - name: Install
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install -e '.[test-dask]'
+
+      - name: Run tests
+        run: |
+          pytest -vs