remove python setup

Author: karlnyr

.github/workflows/run_tests.yml

@@ -15,10 +15,7 @@ jobs:
 
     steps:
     - uses: actions/checkout@v4
-    - name: Set up Python 3.6
-      uses: actions/setup-python@v3
-      with:
-        python-version: '3.6.15'
+
     - name: Create conda/mamba environment using micromamba
       uses: mamba-org/setup-micromamba@v1
       with: