Bump rexml from 3.3.4 to 3.3.6 (#13549)

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

Author: dependabot[bot]

Gemfile.lock

@@ -145,7 +145,7 @@ GEM
     open4 (1.3.4)
     public_suffix (4.0.7)
     rchardet (1.8.0)
-    rexml (3.3.4)
+    rexml (3.3.6)
       strscan
     ruby-macho (2.5.1)
     ruby2_keywords (0.0.5)