Added apt update command to avoid errors and make it consistent with other tests

Author: Cristiano Köhler

.github/workflows/CI.yml

@@ -511,6 +511,7 @@ jobs:
           # create an environment and install everything
           python -m venv ~/test_env
           source ~/test_env/bin/activate
+          sudo apt-get update
           sudo apt install -y libopenmpi-dev openmpi-bin
 
           python -m pip install --upgrade pip