build(deps): bump rexml from 3.2.4 to 3.2.5 in /docs (#273)

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>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

docs/Gemfile.lock

@@ -24,6 +24,7 @@ GEM
       http_parser.rb (~> 0.6.0)
     ethon (0.12.0)
       ffi (>= 1.3.0)
+    eventmachine (1.2.7)
     eventmachine (1.2.7-x64-mingw32)
     execjs (2.7.0)
     faraday (1.3.0)
@@ -31,6 +32,7 @@ GEM
       multipart-post (>= 1.2, < 3)
       ruby2_keywords
     faraday-net_http (1.0.1)
+    ffi (1.14.2)
     ffi (1.14.2-x64-mingw32)
     forwardable-extended (2.6.0)
     gemoji (3.0.1)
@@ -213,6 +215,8 @@ GEM
     multipart-post (2.1.1)
     nokogiri (1.11.1-x64-mingw32)
       racc (~> 1.4)
+    nokogiri (1.11.1-x86_64-linux)
+      racc (~> 1.4)
     octokit (4.20.0)
       faraday (>= 0.9)
       sawyer (~> 0.8.0, >= 0.5.3)
@@ -223,7 +227,7 @@ GEM
     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
@@ -251,6 +255,7 @@ GEM
       tzinfo (>= 1.0.0)
     unf (0.1.4)
       unf_ext
+    unf_ext (0.0.7.7)
     unf_ext (0.0.7.7-x64-mingw32)
     unicode-display_width (1.7.0)
     wdm (0.1.1)
@@ -258,6 +263,7 @@ GEM
 
 PLATFORMS
   x64-mingw32
+  x86_64-linux
 
 DEPENDENCIES
   github-pages