fileutils 1.8.0 on Ruby Gems

What's Changed

Fix ln_sf with multiple sources and target_directory: false by @nobu in #134
[DOC] Fix optional argument descriptions by @akihikodaki in #117
If noop, return before checking the argument by @nobu in #135
Refine ln_sr by @nobu in #136
FileUtils.remove_dir checks directory by @sferik in #132
Just the parent path of the destination symlink should exist by @nobu in #137
A workaround for RBS by @nobu in #138
Make ln_s forward target_directory to ln_sr by @nobu in #139
Add a workflow to sync commits to ruby/ruby by @k0kubun in #143

Full Changelog: v1.7.3...v1.8.0