added dlg_example_cmpts to enable test graph

.github/workflows/run-unit-tests.yml

@@ -37,7 +37,7 @@ jobs:
       - name: Install test dependencies
         run: |
           pip install -U coveralls pytest pytest-cov
-          pip install -U setuptools pip wheel dask
+          pip install -U setuptools pip wheel dask dlg-example-cmpts
 
       - name: Install daliuge-common
         run: pip install -e daliuge-common/