Upgrade the Docker base image to Python 3.12

Python 3.8 is past EOL. The slim image also needs setuptools and wheel for setup.py install.

Author: Hashim1999164

Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.8-slim
+FROM python:3.12-slim
 
 ENV APP_DIR=/usr/src/snappass
 
@@ -11,11 +11,10 @@ WORKDIR $APP_DIR
 COPY ["setup.py", "requirements.txt", "MANIFEST.in", "README.rst", "AUTHORS.rst", "$APP_DIR/"]
 COPY ["./snappass", "$APP_DIR/snappass"]
 
-RUN pip install -r requirements.txt
-
-RUN pybabel compile -d snappass/translations
-
-RUN python setup.py install && \
+# setuptools is required for setup.py install on modern Python slim images
+RUN pip install --no-cache-dir -r requirements.txt setuptools wheel && \
+    pybabel compile -d snappass/translations && \
+    python setup.py install && \
     chown -R snappass $APP_DIR && \
     chgrp -R snappass $APP_DIR