update os-blas-test-matrix to match slycot strategy

Author: murrayrm

.github/workflows/os-blas-test-matrix.yml

@@ -101,6 +101,7 @@ jobs:
   build-conda:
     name: Build conda Py${{ matrix.python }}, ${{ matrix.os }}
     runs-on: ${{ matrix.os }}-latest
+    needs: build-sdist
     strategy:
         fail-fast: false
         matrix: