title: Install package on Travis-ci with sudo:false
body: <p>How can I Iinstall a package on Travis-ci with sudo:false in travis.yml ?</p>
  <p>I have my travis.yml :</p>
  <pre><code>sudo: false
  
  install:
    - wget http://security.ubuntu.com/ubuntu/pool/main/i/icu/libicu52_52.1-3ubuntu0.4_amd64.deb
    - sudo dpkg -i libicu52_52.1-3ubuntu0.4_amd64.deb
  </code></pre>
  <p>I have an error :</p>
  <blockquote>
  <p>sudo: must be setuid root</p>
  <p>The command &quot;sudo dpkg -i libicu52_52.1-3ubuntu0.4_amd64.deb&quot; failed and exited with 1 during .</p>
  </blockquote>