build(deps): bump rexml from 3.2.4 to 3.2.5 in /docs

Bumps [rexml](https://github.com/ruby/rexml) from 3.2.4 to 3.2.5.
- [Release notes](https://github.com/ruby/rexml/releases)
- [Changelog](https://github.com/ruby/rexml/blob/master/NEWS.md)
- [Commits](https://github.com/ruby/rexml/compare/v3.2.4...v3.2.5)

Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/docs/Gemfile.lock b/docs/Gemfile.lock
index 7e516ad..38e1c08 100644
--- a/docs/Gemfile.lock
+++ b/docs/Gemfile.lock
@@ -225,7 +225,7 @@
     rb-fsevent (0.10.4)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    rexml (3.2.4)
+    rexml (3.2.5)
     rouge (3.26.0)
     ruby-enum (0.9.0)
       i18n