CI tests: Use miniconda instead of miniforge

This is to prevent errors in the "Post install conda" step.

Author: jitseniesen

.github/workflows/run-tests.yml

@@ -34,8 +34,8 @@ jobs:
       - name: Install Conda
         uses: conda-incubator/setup-miniconda@v3
         with:
-          miniforge-version: latest
-          auto-update-conda: true
+	  channels: conda-forge
+          conda-remove-defaults: "true"
           python-version: ${{ matrix.PYTHON_VERSION }} 
       - name: Checkout Spyder from git
         if: matrix.SPYDER_SOURCE == 'git'