title: Locale nl_NL missing in docker BitBucket pipeline
body: <p>I'm using this <code>bitbucket-pipelines.yml</code> file to test my application before deploying it on the servers. We're missing the nl_NL locale after installing the dependencies. We're using the following file:</p>
  
  <p>bitbucket-pipelines.yml:</p>
  
  <pre><code>image: php:7.2.6
  
  pipelines:
    default:
      - step:
          name: PHPUnit
          caches:
            - composer
          script:
            - apt-get update &amp;&amp; apt-get install -y unzip git zlib1g-dev libicu-dev g++ locales
            - locale-gen &amp;&amp; locale-gen nl_NL
            - echo "nl_NL UTF-8" &gt;&gt; /etc/locale.gen &amp;&amp; echo "en_EN UTF-8" &gt;&gt; /etc/locale.gen &amp;&amp; echo "enUS UTF-8" &gt;&gt; /etc/locale.gen &amp;&amp; echo "en_GB UTF-8" &gt;&gt; /etc/locale.gen
            - locale -a
  </code></pre>
  
  <p>The locale -a output after installation is as following:</p>
  
  <pre><code>locale -a
  &lt;1s
  + locale -a
  C
  C.UTF-8
  POSIX
  </code></pre>
  
  <p>I did expect the nl_NL locale in this command. This will result in failing tests. How can I fix this error?</p>