add new ci for v3

.github/workflows/v3_ci.yml

@@ -0,0 +1,40 @@
+name: ZarrV3 CI
+
+on:
+  push:
+    branches:
+      - main
+    tags:
+      - "v*"
+  pull_request:
+  workflow_dispatch:
+
+# cancel in-progress runs that use the same workflow and branch
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+
+  test:
+    name: Test zarr-python v3 compatibility
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: 🐍 Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.11"
+          cache-dependency-path: "pyproject.toml"
+          cache: "pip"
+
+      - name: Install Dependencies
+        run: |
+          python -m pip install -U pip
+          # if running a cron job, we add the --pre flag to test against pre-releases
+          python -m pip install .[dev3] ${{ github.event_name == 'schedule' && '--pre' || ''  }}
+
+      - name: 🧪 Run Tests
+        run: pytest