[chores] Fixed dev docker image (updated Python to 3.9.19)

Dockerfile

@@ -1,11 +1,13 @@
-FROM python:3.7.5-slim-buster
+FROM python:3.9.19-slim-bullseye
 
 RUN apt update && \
     apt install --yes zlib1g-dev libjpeg-dev gdal-bin libproj-dev \
     libgeos-dev libspatialite-dev libsqlite3-mod-spatialite \
     sqlite3 libsqlite3-dev openssl libssl-dev fping && \
     rm -rf /var/lib/apt/lists/* /root/.cache/pip/* /tmp/*
 
+RUN pip install -U pip setuptools wheel
+
 COPY requirements-test.txt requirements.txt /opt/openwisp/
 RUN pip install -r /opt/openwisp/requirements.txt && \
     pip install -r /opt/openwisp/requirements-test.txt && \