Use Rake DSL instead of commands of `FileUtils`

- Respect `--verbose(-v)` and `--dry-run(-n)` options.
- Silence warnings to keyword arguments on Ruby 2.7.

1 files changed, 2 insertions, 2 deletions

diff --git a/tasks/doc.rake b/tasks/doc.rake
index 4aec2d0a1..11b76bb3f 100644
--- a/tasks/doc.rake
+++ b/tasks/doc.rake
@@ -25,12 +25,12 @@ end
 
 desc 'clean all built docs'
 task :clean_api_doc do
-  FileUtils.rm_rf 'doc/api'
+  rm_rf 'doc/api'
 end
 
 desc 'clean all built docs'
 task :clean_capi_doc do
-  FileUtils.rm_rf 'doc/capi'
+  rm_rf 'doc/capi'
 end
 
 desc 'clean all built docs'