Remove useless lifetime of ArchiveBuilder `trait ArchiveBuilder<'a>` has a seemingly useless lifetime a, so I remove it. If this is intentional, please reject this PR. ```rust pub trait ArchiveBuilder<'a> { fn add_file(&mut self, path: &Path); fn add_archive( &mut self, archive: &Path, skip: Box<dyn FnMut(&str) -> bool + 'static>, ) -> io::Result<()>; fn build(self: Box<Self>, output: &Path) -> bool; } ```