test: add pyvista for test env

Author: lachlangrose

.github/workflows/tester.yml

@@ -33,7 +33,7 @@ jobs:
       - name: Installing dependencies
         shell: bash -l {0}
         run: |
-          conda install -c conda-forge numpy scipy scikit-image scikit-learn pytest networkx osqp matplotlib -y
+          conda install -c conda-forge numpy scipy scikit-image scikit-learn pyvista networkx osqp matplotlib -y
       - name: Building and install
         shell: bash -l {0}
         run: |