bump rexml

Gemfile.lock

@@ -22,7 +22,7 @@ GEM
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0)
     eventmachine (1.2.7)
-    execjs (2.9.1)
+    execjs (2.10.0)
     ffi (1.17.0)
     ffi (1.17.0-x86_64-darwin)
     ffi (1.17.0-x86_64-linux-gnu)
@@ -62,7 +62,7 @@ GEM
       listen (~> 3.0)
     jekyll-youtube (1.0.0)
       jekyll
-    json (2.7.2)
+    json (2.7.5)
     katex (0.10.0)
       execjs (~> 2.8)
     kramdown (2.4.0)
@@ -100,15 +100,15 @@ GEM
     rb-fsevent (0.11.2)
     rb-inotify (0.11.1)
       ffi (~> 1.0)
-    rexml (3.3.8)
+    rexml (3.3.9)
     rouge (3.30.0)
     safe_yaml (1.0.5)
     sassc (2.4.0)
       ffi (~> 1.9)
     terminal-table (1.8.0)
       unicode-display_width (~> 1.1, >= 1.1.1)
     unicode-display_width (1.8.0)
-    webrick (1.8.2)
+    webrick (1.9.0)
 
 PLATFORMS
   ruby