Dockerfile - use recent alpine

Upgrade python package names to v3 versions.

Drop jfloff/alpine-python, it seems to get us two versions of python
which don't play together.

Don't upgrade pip - seems to cause problems with building

Add in all the prereqs, notably for building py3-cryptography, which
needs a bleedin' rust toolchain

Dockerfile

@@ -1,33 +1,44 @@
+ARG alpine_version=3.13
+
+FROM alpine:$alpine_version
+# retrive alpine_version from before FROM
+ARG alpine_version
+
 ARG PUID=1000
 ARG PGID=1000
+# This is an archive and isn't updated any more
+ARG spotify_version=12.1.51-Linux-x86_64
 
-FROM jfloff/alpine-python:2.7
-ENV PYTHONPATH="/usr/local/lib/python2.7/site-packages:/usr/lib/python2.7/site-packages"
+#ENV PYTHONPATH="/usr/local/lib/python$python_version/site-packages:/usr/lib/python$python_version/site-packages"
 
 WORKDIR /mopidy
 
 RUN \
   echo "* Updating Package Repositories" \
-    && echo 'http://dl-cdn.alpinelinux.org/alpine/v3.9/main' >> /etc/apk/repositories \
-    && echo 'http://dl-cdn.alpinelinux.org/alpine/v3.9/community' >> /etc/apk/repositories \
+    && echo "http://dl-cdn.alpinelinux.org/alpine/v${alpine_version}/main" >> /etc/apk/repositories \
+    && echo "http://dl-cdn.alpinelinux.org/alpine/v${alpine_version}/community" >> /etc/apk/repositories \
     && apk upgrade --no-cache \
-    && pip install --upgrade pip \
   && echo "* Installing Runtime Packages" \
     && apk add -U --no-cache \
       coreutils \
+      build-base \
+      rust \
+      cargo \
       su-exec \
       libxml2-dev \
       libxslt-dev \
       libffi-dev \
       openssl-dev \
-      python2-dev \
+      python3-dev \
+      py3-pip \
+      py3-wheel \
       libcdio \
       libcaca \
       libvpx \
       v4l-utils-libs \
-      py2-crypto \
-      py2-gst \
-      py-gobject \
+      py3-crypto \
+      py3-gst \
+      py3-gobject3 \
       mailcap \
       icecast \
       gstreamer \
@@ -35,14 +46,14 @@ RUN \
       gst-plugins-base \
       gst-plugins-good \
       gst-plugins-ugly \
-    && pip install -U \
+    && pip3 install -U \
       pyopenssl \
       youtube-dl \
       pyasn1 \
-    && wget -c https://mopidy.github.io/libspotify-archive/libspotify-12.1.51-Linux-x86_64-release.tar.gz -O - | tar -xzC /tmp \
-      && make install -C /tmp/libspotify-12.1.51-Linux-x86_64-release prefix=/usr/local || true \
+    && wget -c https://mopidy.github.io/libspotify-archive/libspotify-${spotify_version}-release.tar.gz -O - | tar -xzC /tmp \
+      && make install -C /tmp/libspotify-${spotify_version}-release prefix=/usr/local || true \
   && echo "* Installing Mopidy + Extensions" \
-    && pip install -U \
+    && pip3 install -U \
       Mopidy \
       Mopidy-Iris \
       Mopidy-Spotify-Web \
@@ -53,7 +64,7 @@ RUN \
   && echo "* Creating Mopidy User" \
     && addgroup -g ${PGID} mopidy \
     && adduser -h /mopidy -s /bin/sh -D -G mopidy -u $PUID mopidy \
-    && echo "mopidy ALL=NOPASSWD: /usr/local/lib/pyenv/versions/2.7.16/lib/python2.7/site-packages/mopidy_iris/system.sh" >> /etc/sudoers \
+    && echo "mopidy ALL=NOPASSWD: /usr/local/lib/pyenv/versions/*/lib/python*/site-packages/mopidy_iris/system.sh" >> /etc/sudoers \
   && echo "* Cleaning up" \
     && rm -rf /var/cache/apk/* \
     && rm -rf /tmp/* \