Remove Sphinx build step from "pytest" CI workflow

.github/workflows/pytest.yaml

@@ -25,7 +25,8 @@ jobs:
         python:
         # llvmlite (thus numba, thus sparse) usually lags the latest Python
         # release. Only test SparseDataArray where possible.
-        # Earliest version supported by genno; matches xarray/setup.cfg
+        # Earliest version supported by genno = earliest Python that has not
+        # reached EOL
         - {version: "3.8", extras: ",sparse"}
         - {version: "3.9", extras: ",sparse"}
         - {version: "3.10", extras: ",sparse"}
@@ -38,7 +39,7 @@ jobs:
         # Compiling these on the job runner requires a more elaborate build
         # environment, currently out of scope for genno. Exclude these versions
         # from CI.
-        # - {version: "3.12.0-alpha.2", extras: ""}  # Development version
+        # - {version: "3.13.0-rc.1", extras: ""}  # Development version
 
       fail-fast: false
 
@@ -61,14 +62,15 @@ jobs:
         macos-skip-brew-update: true
 
     - name: Install the Python package and dependencies
-      run: pip install --upgrade --upgrade-strategy=eager .[docs,tests${{ matrix.python.extras }}]
+      run: pip install --upgrade --upgrade-strategy=eager .[tests${{ matrix.python.extras }}]
 
     - name: Run test suite using pytest
-      run: pytest genno --trace-config --color=yes --verbose --cov-report=xml --cov-report=term --numprocesses auto
-
-    - name: Test documentation build using Sphinx
-      if: startsWith(matrix.os, 'ubuntu')
-      run: make -C doc html
+      run: |
+        pytest genno \
+          --trace-config --color=yes --verbose \
+          --cov-report=xml --cov-report=term \
+          --numprocesses auto
+      shell: bash
 
     - name: Upload test coverage to Codecov.io
       uses: codecov/codecov-action@v3