chore(deps): update dependency rexml to v3.4.3

Author: renovate[bot]

Gemfile.lock

@@ -542,7 +542,7 @@ GEM
       railties (>= 5.2)
     reverse_markdown (3.0.0)
       nokogiri
-    rexml (3.4.2)
+    rexml (3.4.4)
     rotp (6.3.0)
     rouge (4.4.0)
     rqrcode (2.2.0)