CI/CD: add torch installation

Author: maximpavliv

.github/workflows/testing.yml

@@ -54,5 +54,5 @@ jobs:
         shell: bash -el {0}  # Important: activates the conda environment
         run: |
           python -m pip install --upgrade pip wheel poetry
-          python -m poetry install --extras "tf"
+          python -m poetry install --extras "tf" --extras "pytorch"
           python -m poetry run dlc-live-test --nodisplay