
* filter tags correctly when `since_tag` is set to most recent tag Before this fix [`filtered_tags`](https://github.com/skywinder/github-changelog-generator/blob/master/lib/github_changelog_generator/generator/generator_generation.rb#L132) was empty which caused a fallback to the last tag in the sorted_tags array (which is the oldest tag). There for no issues and PRs were filtered in that case. fixes #555 fixes #304