Stop using mamba in action

Not needed for anything.

.github/workflows/build.yaml

@@ -19,46 +19,37 @@ jobs:
           # Need to clone everything for the git tags.
           fetch-depth: 0
 
-      - uses: conda-incubator/setup-miniconda@v3
+      - name: Set up Python
+        uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
-          channels: conda-forge,defaults
-          channel-priority: strict
-          show-channel-urls: true
-          miniforge-variant: Mambaforge
-          use-mamba: true
+          cache: "pip"
+          cache-dependency-path: "setup.cfg"
 
       - name: Update pip/wheel infrastructure
-        shell: bash -l {0}
         run: |
-          mamba install -y -q pip wheel
+          python -m pip install --upgrade pip
           pip install uv
-
+          uv pip install --system wheel
       - name: Install dependencies
-        shell: bash -l {0}
         run: |
-          uv pip install -r requirements.txt
+          uv pip install --system -r requirements.txt
 
       # We have two cores so we can speed up the testing with xdist
       - name: Install pytest packages
-        shell: bash -l {0}
         run: |
-          uv pip install \
+          uv pip install --system \
             pytest pytest-xdist pytest-cov
 
       - name: List installed packages
-        shell: bash -l {0}
         run: |
-          conda list
-          pip list -v
+          uv pip list -v
 
       - name: Build and install
-        shell: bash -l {0}
         run: |
-          uv pip install -v --no-deps -e .
+          uv pip install --system -v --no-deps -e .
 
       - name: Run tests
-        shell: bash -l {0}
         env:
           DAF_BUTLER_MIGRATE_DIR: .
           DAF_BUTLER_MIGRATE_MIGRATIONS: ./migrations