specify bash shell.

Author: Dani Sim

.github/workflows/ci-workflow.yaml

@@ -63,6 +63,7 @@ jobs:
           conda config --set always_yes yes --set changeps1 no
           conda update -q conda
           conda create -n testenv --yes -c conda-forge pip python=${{ matrix.python }} numpy=${{ matrix.numpy }} pandas=${{ matrix.pandas }} scipy=${{ matrix.scipy }} libgfortran=${{ matrix.libgfortran }}
+        shell: bash
 
 
       - name: Install dependencies