title: SBT native packager: Unzip artifact in %install
body: <p>I am using sbt-native-packager (0.8.0) with SBT 0.13.5. I have a zip file that should be unzipped as part of RPM installation. In a RPM spec it will be under <code>%install</code> section, where will I define it using sbt-native-packager? I can unzip the artifact and add the unzipped folder as <code>linuxPackageMapping</code> but I wanted to check if there is a way to include the zip in RPM and unzip it during installation.</p>