Update script from a tag uses SNAPSHOT dependencies/parent

This makes it difficult to use the update script during testing because even if the script is taken from a Weld tag, the following actions still need to be executed:

1) Weld SNAPSHOT needs to be built (due to Weld release script having a dependency on a SNAPSHOT version of parent)
2) Weld version needs to be overridden using "weld.update.version" (otherwise, the SNAPSHOT version is used again, which is not desider)