Add conda defaults channel configuration

Add conda defaults channel to workflow

Author: jnettels

.github/workflows/python_jobs.yml

@@ -22,6 +22,9 @@ jobs:
         update-conda: false
         python-version: ${{ matrix.python-version }}
 
+    - name: Add conda defaults channel
+      run: conda config --add channels defaults
+
     - name: Initialize powershell for conda (Windows only)
       if: runner.os == 'Windows'
       run: conda init powershell