Bump rexml from 3.2.5 to 3.3.3

Bumps [rexml](https://github.com/ruby/rexml) from 3.2.5 to 3.3.3.
- [Release notes](https://github.com/ruby/rexml/releases)
- [Changelog](https://github.com/ruby/rexml/blob/master/NEWS.md)
- [Commits](ruby/rexml@v3.2.5...v3.3.3)

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

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Gemfile.lock

@@ -57,15 +57,16 @@ GEM
     rb-fsevent (0.10.4)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    rexml (3.2.5)
+    rexml (3.3.3)
+      strscan
     rouge (3.3.0)
     safe_yaml (1.0.5)
     sass (3.7.4)
       sass-listen (~> 4.0.0)
     sass-listen (4.0.0)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
-    wdm (0.1.1)
+    strscan (3.1.0)
 
 PLATFORMS
   ruby
@@ -80,7 +81,6 @@ DEPENDENCIES
   kramdown
   kramdown-parser-gfm
   rouge
-  wdm (>= 0.1.0)
 
 BUNDLED WITH
    2.4.21