upgrade docker to alpine 3.18:

* enables chiptune player
* smaller containers (generate pycache at runtime)

scripts/docker/Dockerfile.iv

@@ -5,14 +5,19 @@ LABEL   org.opencontainers.image.url="https://github.com/9001/copyparty" \
         org.opencontainers.image.licenses="MIT" \
         org.opencontainers.image.title="copyparty-iv" \
         org.opencontainers.image.description="copyparty with Pillow, FFmpeg, libvips (image/audio/video thumbnails, audio transcoding, media tags)"
+ENV     PYTHONPYCACHEPREFIX=/tmp/pyc
 
-RUN     apk --no-cache add \
+RUN     apk add -U !pyc \
             wget \
             py3-pillow py3-pip py3-cffi \
             ffmpeg \
             vips-jxl vips-heif vips-poppler vips-magick \
+        && apk add -t .bd \
+            bash wget gcc g++ make cmake patchelf \
+            python3-dev py3-wheel \
         && python3 -m pip install pyvips \
-        && apk del py3-pip \
+        && apk del py3-pip .bd \
+        && rm -rf /var/cache/apk/* /tmp/pyc \
         && mkdir /cfg /w \
         && chmod 777 /cfg /w \
         && echo % /cfg > initcfg