Use uv on CI

.github/workflows/main.yml

@@ -37,6 +37,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
+      - name: Install uv
+        uses: astral-sh/setup-uv@v5
 
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v5
@@ -47,9 +49,9 @@ jobs:
 
       - name: Install project dependencies
         run: |
-          pip install --upgrade pip setuptools
-          pip install codecov '.[tests]' '${{ matrix.urllib3-requirement }}'
-          pip check
+          uv pip install --system --upgrade pip setuptools
+          uv pip install --system codecov '.[tests]' '${{ matrix.urllib3-requirement }}'
+          uv pip check
 
       - name: Allow creation of user namespaces (e.g. to the unshare command)
         run: |