Ignore reads configuration files #4157
Description
The ignore crate reads .gitignore files (and others) to know which files to list or not. It means that some files that are not listed under package.exclude in the manifest may still be excluded "silently" if a .gitignore is copied to the package directory. It happened here for example.
The crate allows to disable this feature (and other similar behaviors). But that would mean that previously bundled packages may contain different files when the new version of the bundler runs again, which would break reproducibility.