Bump ffi from 1.9.6 to 1.11.1

Bumps [ffi](https://github.com/ffi/ffi) from 1.9.6 to 1.11.1.
- [Release notes](https://github.com/ffi/ffi/releases)
- [Changelog](https://github.com/ffi/ffi/blob/master/CHANGELOG.md)
- [Commits](ffi/ffi@v1.9.6...1.11.1)

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

Author: dependabot[bot]

Gemfile.lock

@@ -11,18 +11,27 @@ GEM
     cri (2.6.1)
       colored (~> 1.2)
     diff-lcs (1.2.5)
-    ffi (1.9.6)
+    em-websocket (0.5.1)
+      eventmachine (>= 0.12.9)
+      http_parser.rb (~> 0.6.0)
+    eventmachine (1.2.7)
+    ffi (1.11.1)
     formatador (0.2.5)
     guard (2.6.1)
       formatador (>= 0.2.4)
       listen (~> 2.7)
       lumberjack (~> 1.0)
       pry (>= 0.9.12)
       thor (>= 0.18.1)
+    guard-livereload (2.3.1)
+      em-websocket (~> 0.5)
+      guard (~> 2.0)
+      multi_json (~> 1.8)
     guard-nanoc (1.0.2)
       guard (>= 1.8.0)
       nanoc (>= 3.6.3)
     hitimes (1.2.2)
+    http_parser.rb (0.6.0)
     kramdown (1.4.2)
     listen (2.7.11)
       celluloid (>= 0.15.2)
@@ -31,6 +40,7 @@ GEM
     lumberjack (1.0.9)
     method_source (0.8.2)
     mini_portile (0.6.0)
+    multi_json (1.14.1)
     nanoc (3.7.3)
       cri (~> 2.3)
     nanoc-cachebuster (0.3.1)
@@ -69,7 +79,7 @@ GEM
     thor (0.19.1)
     timers (4.0.1)
       hitimes
-    yajl-ruby (1.3.0)
+    yajl-ruby (1.1.0)
 
 PLATFORMS
   ruby