Update regression test workflow

.github/workflows/run-regression-test.yml

@@ -11,29 +11,32 @@ jobs:
   run_fmu_dummy:
     name: Run FMU dummy
     runs-on: ubuntu-latest
-    container: precice/precice:nightly
+    container:
+      image: precice/precice:nightly
+      options: --user root
     steps:
-
       - name: Checkout Repository
-        uses: actions/checkout@v2      
-
+        uses: actions/checkout@v4    
       - name: Install Dependencies
         run: |
           apt-get -qq update
-          apt-get -qq install python3-dev python3-pip git python-is-python3 pkg-config
-          python -m pip install --upgrade pip
-          pip install fmpy
-
-      - name: Install fmiprecice
+          apt-get -qq install python3-pip python3.12-venv
+          rm -rf /var/lib/apt/lists/*
+      - name: Create venv
         run: |
-            pip3 install --user .
-
+          python3 -m venv .venv
+      - name: Activate venv
+        # see https://stackoverflow.com/a/74669486
+        run: |
+          . .venv/bin/activate
+          echo PATH=$PATH >> $GITHUB_ENV   
+      - name: Run pip install
+        run:  pip install .
       - name: Run coupling of two Dummy FMUs
         timeout-minutes: 3
         run: |
           cd tests/
-          cd SolverOne/ && python3 ../../fmiprecice/runner.py ./fmi-settings.json ./precice-settings.json & cd SolverTwo/ && python3 ../../fmiprecice/runner.py ./fmi-settings.json ./precice-settings.json
-
+          cd SolverOne/ && fmiprecice ./fmi-settings.json ./precice-settings.json & cd SolverTwo/ && fmiprecice ./fmi-settings.json ./precice-settings.json
       - name: Check the result
         timeout-minutes: 3
         run: |