I have a file which maintains a build-number for release build. Everytime a release build is made, this number is incremented and the file is saved into svn repository.
Using pluginManagement will not cause the build plugin to run. It is used to specify plugin version and configuration information to child POMs. Also you're missing the 'profile' child element of 'profiles'. Lastly, unless you plan on activating the profile via -P, you'll need some activation criteria.