Bump rexml from 3.2.5 to 3.2.8 in /thymeleaf-layout-dialect-docs

Bumps [rexml](https://github.com/ruby/rexml) from 3.2.5 to 3.2.8.
- [Release notes](https://github.com/ruby/rexml/releases)
- [Changelog](https://github.com/ruby/rexml/blob/master/NEWS.md)
- [Commits](ruby/rexml@v3.2.5...v3.2.8)

---
updated-dependencies:
- dependency-name: rexml
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>

thymeleaf-layout-dialect-docs/Gemfile.lock

@@ -9,6 +9,7 @@ GEM
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0.6.0)
     eventmachine (1.2.7)
+    eventmachine (1.2.7-x64-mingw32)
     ffi (1.15.3)
     forwardable-extended (2.6.0)
     http_parser.rb (0.6.0)
@@ -58,12 +59,16 @@ GEM
     rb-fsevent (0.11.0)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    rexml (3.2.5)
+    rexml (3.2.8)
+      strscan (>= 3.0.9)
     rouge (3.26.0)
     rubyzip (2.3.2)
     safe_yaml (1.0.5)
     sassc (2.4.0)
       ffi (~> 1.9)
+    sassc (2.4.0-x64-mingw32)
+      ffi (~> 1.9)
+    strscan (3.1.0)
     terminal-table (2.0.0)
       unicode-display_width (~> 1.1, >= 1.1.1)
     unicode-display_width (1.7.0)
@@ -74,6 +79,7 @@ PLATFORMS
   x64-mingw32
   x86_64-darwin-19
   x86_64-darwin-20
+  x86_64-linux
 
 DEPENDENCIES
   jekyll