Bump rexml from 3.2.8 to 3.3.9 (#204)

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

Author: dependabot[bot]

Gemfile.lock

@@ -48,13 +48,11 @@ GEM
     rb-fsevent (0.11.2)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    rexml (3.2.8)
-      strscan (>= 3.0.9)
+    rexml (3.3.9)
     rouge (3.30.0)
     safe_yaml (1.0.5)
     sassc (2.4.0)
       ffi (~> 1.9)
-    strscan (3.1.0)
     terminal-table (2.0.0)
       unicode-display_width (~> 1.1, >= 1.1.1)
     unicode-display_width (1.8.0)