Fix sdist build dependencies

.github/workflows/wheel_tests_and_release.yml

@@ -162,7 +162,7 @@ jobs:
       - name: Install build tools
         run: |
           python -m pip install --upgrade pip
-          pip install build setuptools_scm
+          pip install build numpy cython setuptools_scm
 
       - name: Build the source distribution
         run: |