update docker file as per mail from ITC

Dockerfile

 # Specify parent image. Please select a fixed tag here.
-ARG BASE_IMAGE=registry.git.rwth-aachen.de/jupyter/profiles/rwth-courses:latest
+#ARG BASE_IMAGE=registry.git.rwth-aachen.de/jupyter/profiles/rwth-courses:latest
+ARG BASE_IMAGE=registry.jupyter.rwth-aachen.de/profiles/rwth-courses-python-3.11:latest
 FROM ${BASE_IMAGE}
 
+ARG conda_env=python311
+ARG py_ver=3.11
+ARG disp_name="Python 3.11 (ipykernel)"
+
+
 # Install packages via requirements.txt
 ADD requirements.txt .
-RUN pip install -r requirements.txt
+# RUN pip install -r requirements.txt
+RUN "${CONDA_DIR}/envs/${conda_env}/bin/pip" install --no-cache-dir -r requirements.txt
 
 # .. Or update conda base environment to match specifications in environment.yml
 # ADD environment.yml /tmp/environment.yml