update doctest.yml to install control

Author: murrayrm

.github/workflows/doctest.yml

@@ -27,7 +27,11 @@ jobs:
     - name: Install full dependencies
       shell: bash -l {0}
       run: |
-        mamba install cvxopt pandas slycot 
+        mamba install cvxopt pandas slycot
+
+    - name: Install python-control from source
+      run: |
+        conda run -n doctest-env pip install .
 
     - name: Run doctest
       shell: bash -l {0}