Impossible to do global exclusion for packaging #13
Description
Right now, it's possible to exclude files for packaging using negation (!) in the match rule, but this has to be done for each package.
When a user has lots of packages defined and a number of temporary files across his folders (like *.log, *.keep that are gitignored), with global matches like (something/**/*) those files would land in the packages inadvertently.
Defining a rule like !*.log for each package is not very handy, but a single global ignore pattern would be useful in this situation.