title: Docker: Alpine linux community package not found
body: <p>I am trying to create a container with the following Dockerfile:</p>
  
  <pre><code>FROM python:3.6-alpine
  
  RUN apk add --update alpine-sdk make gcc python3-dev python-dev libxslt-dev \
       libxml2-dev libc-dev openssl-dev libffi-dev zlib-dev py-pip openssh \
       py3-lxml@main py3-numpy@community \
       mariadb-dev libjpeg-dev zlib1g-dev &amp;&amp; rm -rf /var/cache/apk/*
  </code></pre>
  
  <p>I added <code>py3-lxml@main</code> and <code>py3-numpy@community</code> based on <a href="https://stackoverflow.com/a/50443531/4764353">this advice</a> as building wheel for <code>numpy</code> and <code>lxml</code> takes ages.</p>
  
  <p>I have used the package names as specified on the official <a href="https://pkgs.alpinelinux.org/packages?name=*numpy&amp;branch=v3.6" rel="nofollow noreferrer">Alpine repo page</a>, but I get the following error:</p>
  
  <pre><code>WARNING: The repository tag for world dependency 'py3-lxml@main' does not exist
  WARNING: The repository tag for world dependency 'py3-numpy@community' does not exist*
  </code></pre>
  
  <p>Why is that and how can I get those packages?</p>