you should be careful to update your libs all time, just because a new release is ready for download.
it could well be that some libraries are not down compatible (e.g. introducing new/other bug through bug fixing), and then you end up with searching for bugs in your code base, though the error is somewhere else. i know it is not very likely (if you use stable libraries like commons), but still it is sometimes unsure.
i would only update 3rd party libraries, when it is neccessary, i.e. a bug, which breaks your program was fixed, a new release with new functionality was developed or similar and i would do it manually (including looking at release notes, if it is worth to upgrade).
or what is the reason why you want to update libraries so regulary, that you want to include it in your automatic build process? AFAIK stable libraries anyway don't get updated very often.