Switch base image to python:3.12

Dockerfile

@@ -1,4 +1,4 @@
-FROM ubuntu
+FROM python:3.12
 LABEL org.opencontainers.image.title="gtfs-hub"
 LABEL org.opencontainers.image.description="Collecting, shape-enhancing, validating, fixing and (partially) merging GTFS feeds."
 LABEL org.opencontainers.image.authors="MITFAHR|DE|ZENTRALE <hb@mfdz.de>"
@@ -10,28 +10,23 @@ WORKDIR /gtfs-hub
 
 RUN apt-get update && apt-get install -y \
     make \
-    bash \
-    moreutils \
-    curl \
     zip \
     miller \
     ca-certificates \
-    gnupg \
     lsb-release \
-    python3 \
-    git \
-  && curl -fsSL https://download.docker.com/linux/ubuntu/gpg | gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg \
-  && echo \
-    "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu \
-    $(lsb_release -cs) stable" | tee /etc/apt/sources.list.d/docker.list > /dev/null \
+ && install -m 0755 -d /etc/apt/keyrings \
+ && curl -fsSL https://download.docker.com/linux/debian/gpg | gpg --dearmor -o /etc/apt/keyrings/docker.gpg \
+ && chmod a+r /etc/apt/keyrings/docker.gpg \
+ && echo \
+  "deb [arch="$(dpkg --print-architecture)" signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/debian \
+  "$(. /etc/os-release && echo "$VERSION_CODENAME")" stable" | \
+   tee /etc/apt/sources.list.d/docker.list > /dev/null \
   && apt-get update && apt-get install -y \
     docker-ce-cli \
   && apt-get clean
 
 ADD requirements.txt .
-RUN curl https://bootstrap.pypa.io/get-pip.py > get-pip.py && \
-  python3 get-pip.py && \
-  pip install -r requirements.txt
+RUN pip install -r requirements.txt
 ADD scripts/ scripts/
 ADD patch_raw_gtfs.sh patch_filtered_gtfs.sh ./
 ADD download.sh .