ci: Add Kubernetes and REANA dependencies to CI (#66)

* Install 'kubernetes' and 'reana' extras in CI before running tests
* Restrict setuptools<58.0.0 to allow for installation of reana-client
   - c.f. reanahub/reana-client#558

.github/workflows/ci.yml

@@ -37,8 +37,9 @@ jobs:
 
     - name: Install Python dependencies
       run: |
-        python -m pip install --upgrade pip setuptools wheel
-        python -m pip --quiet install --no-cache-dir .[develop,local]
+        # RE: setuptools c.f. https://github.com/reanahub/reana-client/issues/558
+        python -m pip install --upgrade pip "setuptools<58.0.0" wheel
+        python -m pip --quiet install --no-cache-dir .[develop,local,kubernetes,reana]
         python -m pip list
 
     - name: Run unit tests