title: Cannot install php-mbstring on ubuntu 18.04
body: <p>I'm using ubuntu 18.04.
  I'm trying to install mbstring but terminall show error:</p>
  
  <pre><code>php-mbstring : Depends: php7.2-mbstring but it is not going to be installed
  </code></pre>
  
  <p>So I' trying to install php7.2-mbstring but error again:</p>
  
  <pre><code>php7.2-mbstring : Depends: php7.2-common (= 7.2.3-1ubuntu1) but 7.2.7-0ubuntu0.18.04.2 is to be installed
  </code></pre>
  
  <p>Sorry for my bad english.
  Anyone have idea how to fix this :(</p>