Fix non-editable install

Signed-off-by: Keith Battocchi <kebatt@microsoft.com>

Author: kbattocchi

.github/workflows/ci.yml

@@ -145,6 +145,8 @@ jobs:
     - name: Install graphviz
       run: sudo apt-get -yq install graphviz
       if: ${{ matrix.install_graphviz }}
+    - name: Build extensions
+      run: uv pip install --system oldest-supported-numpy "cython<3" && python setup.py build_ext --inplace
     # Add verbose flag to pip installation if in debug mode
     - name: Install econml
       run: uv pip install --system .${{ matrix.extras }} ${{ fromJSON('["","-v"]')[runner.debug] }} ${{ env.use_lkg && '-r lkg-notebook.txt' }}