title: maven-release-plugin in multi-module project having a seperate git repository for each module
body: <p>I wonder if it's possible to use the maven-release-plugin in a multi module project where each module has its own git repository? Something like this:</p>
  
  <pre><code>parent/
    .git/
    pom.xml
  module1/
    .git/
    pom.xml
  </code></pre>
  
  <p>I set up a simple test (under linux) and it fails for the "git add" command (simplyfied):</p>
  
  <pre><code>cd parent &amp;&amp; git add -- pom.xml /.../module1/pom.xml
  </code></pre>
  
  <p>The error message is</p>
  
  <pre><code>fatal: /.../module1/pom.xml: '/.../module1/pom.xml' is outside repository
  </code></pre>
  
  <p>I understand that this git command can't work. Is maven-release-plugin able to do a seperate "git add" command for each repository?</p>
  
  <p>Just for the case the answer is NO: Assume i only have a single git repository. Does it matter whether i use a flat hierarchy or a nested one?</p>
  
  <p>Are there any other options for automated versioning/releasing and keeping multiple git repositories?</p>