Migrate flux tests to Python 3.13 (#877)

* Migrate flux tests to Python 3.13

* Update pipeline.yml

* Update environment-integration.yml

* Update environment-integration.yml

* Update environment-integration.yml

Author: jan-janssen

.github/workflows/pipeline.yml

@@ -149,7 +149,7 @@ jobs:
       - name: Setup Mambaforge
         uses: conda-incubator/setup-miniconda@v3
         with:
-          python-version: "3.12"
+          python-version: "3.13"
           miniforge-version: latest
           channels: conda-forge
           conda-remove-defaults: "true"
@@ -174,7 +174,7 @@ jobs:
       - name: Setup Mambaforge
         uses: conda-incubator/setup-miniconda@v3
         with:
-          python-version: "3.12"
+          python-version: "3.13"
           miniforge-version: latest
           channels: conda-forge
           conda-remove-defaults: "true"
@@ -202,7 +202,7 @@ jobs:
         cat .ci_support/environment-mpich.yml
     - uses: conda-incubator/setup-miniconda@v3
       with:
-        python-version: '3.12'
+        python-version: '3.13'
         miniforge-version: latest
         channels: conda-forge
         conda-remove-defaults: "true"
@@ -233,7 +233,7 @@ jobs:
         cat .ci_support/environment-openmpi.yml
     - uses: conda-incubator/setup-miniconda@v3
       with:
-        python-version: '3.12'
+        python-version: '3.13'
         miniforge-version: latest
         channels: conda-forge
         conda-remove-defaults: "true"