Bump addressable from 2.4.0 to 2.8.1 in /travis-ci

travis-ci/Gemfile.lock

@@ -1,33 +1,46 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    addressable (2.4.0)
-    backports (3.11.4)
-    ethon (0.11.0)
-      ffi (>= 1.3.0)
-    faraday (0.15.3)
+    activesupport (5.2.8.1)
+      concurrent-ruby (~> 1.0, >= 1.0.2)
+      i18n (>= 0.7, < 2)
+      minitest (~> 5.1)
+      tzinfo (~> 1.1)
+    addressable (2.8.1)
+      public_suffix (>= 2.0.2, < 6.0)
+    backports (3.23.0)
+    concurrent-ruby (1.1.10)
+    ethon (0.15.0)
+      ffi (>= 1.15.0)
+    faraday (0.17.5)
       multipart-post (>= 1.2, < 3)
-    faraday_middleware (0.12.2)
+    faraday_middleware (0.14.0)
       faraday (>= 0.7.4, < 1.0)
-    ffi (1.9.25)
-    gh (0.15.1)
-      addressable (~> 2.4.0)
-      backports
+    ffi (1.15.5)
+    gh (0.16.0)
+      activesupport (~> 5.0)
+      addressable (~> 2.4)
       faraday (~> 0.8)
+      faraday_middleware (~> 0.14)
       multi_json (~> 1.0)
       net-http-persistent (~> 2.9)
       net-http-pipeline
     highline (1.7.10)
-    json (2.1.0)
-    launchy (2.4.3)
-      addressable (~> 2.3)
-    multi_json (1.13.1)
-    multipart-post (2.0.0)
+    i18n (1.12.0)
+      concurrent-ruby (~> 1.0)
+    json (2.6.2)
+    launchy (2.5.0)
+      addressable (~> 2.7)
+    minitest (5.16.3)
+    multi_json (1.15.0)
+    multipart-post (2.2.3)
     net-http-persistent (2.9.4)
     net-http-pipeline (1.0.1)
+    public_suffix (5.0.0)
     pusher-client (0.6.2)
       json
       websocket (~> 1.0)
+    thread_safe (0.3.6)
     travis (1.8.9)
       backports
       faraday (~> 0.9)
@@ -39,7 +52,9 @@ GEM
       typhoeus (~> 0.6, >= 0.6.8)
     typhoeus (0.8.0)
       ethon (>= 0.8.0)
-    websocket (1.2.8)
+    tzinfo (1.2.10)
+      thread_safe (~> 0.1)
+    websocket (1.2.9)
 
 PLATFORMS
   ruby