Add pyopencl to dependency installs (#174)

* Add pyopencl to dependency installs

OpenCL was not actually being tested as pyopencl was not installed.

* Reduce installation to 1 liner

.github/workflows/test.yml

@@ -29,6 +29,6 @@ jobs:
       with:
         python-version: 3.8
     - name: Install Dependencies
-      run: pip install -r requirements.txt
+      run: pip install -e '.[gpu,testing]'
     - name: Run Pytest
       run: python -m pytest -s -v