Update CI to use pixi as well

.github/workflows/ci.yml

@@ -20,18 +20,15 @@ jobs:
       - name: Checkout repo
         uses: actions/checkout@v4
 
-      - name: Setup Python
-        uses: actions/setup-python@v5
+      - name: Setup pixi
+        uses: prefix-dev/setup-[email protected]
         with:
-          python-version: 3.9
-          cache: 'pip'
-          cache-dependency-path: pyproject.toml
-
-      - name: Install Python packages
-        run: pip install ".[lint]"
+          pixi-version: v0.32.0
+          environments: dev
+          activate-environment: true
 
       - name: Run ruff
-        run: ruff check .
+        run: pixi run lint
 
   build:
     name: Build
@@ -41,22 +38,18 @@ jobs:
       - name: Checkout repo
         uses: actions/checkout@v3
 
-      - name: Setup Python
-        uses: actions/setup-python@v5
+      - name: Setup pixi
+        uses: prefix-dev/setup-[email protected]
         with:
-          python-version: 3.9
-
-      - name: Install Python packages
-        run: |
-          pip install --upgrade pip
-          pip install build twine
-          pip --verbose install .
+          pixi-version: v0.32.0
+          environments: dev
+          activate-environment: true
 
       - name: Print package version
         run: python -c "from flopy4 import version; print(version.__version__)"
 
       - name: Build package
-        run: python -m build
+        run: pixi run build
 
   test:
     name: Test
@@ -68,7 +61,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ ubuntu-22.04, macos-12, windows-2022 ]
-        python: [ 3.9, "3.10", "3.11", "3.12" ]
+        python: [ "310", "311", "312" ]
     env:
       GCC_V: 11
     steps:
@@ -81,13 +74,12 @@ jobs:
         with:
           repo: modflow6-nightly-build
 
-      - name: Setup Python
-        uses: actions/setup-python@v5
+      - name: Setup pixi
+        uses: prefix-dev/setup-[email protected]
         with:
-          python-version: ${{ matrix.python }}
-
-      - name: Install Python packages
-        run: pip install ".[test]"
+          pixi-version: v0.32.0
+          environments: test${{ matrix.python }}
+          activate-environment: true
 
       - name: Run tests
-        run: pytest -v -n auto
+        run: pixi run test