Update example (#391)

* Update dependencies

* Increase secret length to 64 to satisfy rack-session encryptor

example/Gemfile.lock

@@ -1,54 +1,69 @@
 PATH
   remote: ..
   specs:
-    omniauth-facebook (8.0.0)
-      omniauth-oauth2 (~> 1.2)
+    omniauth-facebook (9.0.1)
+      omniauth-oauth2 (>= 1.2, < 3)
 
 GEM
   remote: https://rubygems.org/
   specs:
-    backports (3.15.0)
-    faraday (1.1.0)
-      multipart-post (>= 1.2, < 3)
-      ruby2_keywords
-    hashie (4.1.0)
-    jwt (2.2.2)
-    multi_json (1.14.1)
-    multi_xml (0.6.0)
-    multipart-post (2.1.1)
-    mustermann (1.1.1)
+    base64 (0.2.0)
+    bigdecimal (3.1.8)
+    faraday (2.9.2)
+      faraday-net_http (>= 2.0, < 3.2)
+    faraday-net_http (3.1.0)
+      net-http
+    hashie (5.0.0)
+    jwt (2.8.2)
+      base64
+    multi_json (1.15.0)
+    multi_xml (0.7.1)
+      bigdecimal (~> 3.1)
+    mustermann (3.0.0)
       ruby2_keywords (~> 0.0.1)
-    oauth2 (1.4.4)
-      faraday (>= 0.8, < 2.0)
+    net-http (0.4.1)
+      uri
+    oauth2 (2.0.9)
+      faraday (>= 0.17.3, < 3.0)
       jwt (>= 1.0, < 3.0)
-      multi_json (~> 1.3)
       multi_xml (~> 0.5)
-      rack (>= 1.2, < 3)
-    omniauth (1.9.1)
+      rack (>= 1.2, < 4)
+      snaky_hash (~> 2.0)
+      version_gem (~> 1.1)
+    omniauth (2.1.2)
       hashie (>= 3.4.6)
-      rack (>= 1.6.2, < 3)
-    omniauth-oauth2 (1.7.0)
-      oauth2 (~> 1.4)
-      omniauth (~> 1.9)
-    rack (2.2.3)
-    rack-protection (2.0.8.1)
-      rack
-    ruby2_keywords (0.0.2)
-    sinatra (2.0.8.1)
-      mustermann (~> 1.0)
-      rack (~> 2.0)
-      rack-protection (= 2.0.8.1)
+      rack (>= 2.2.3)
+      rack-protection
+    omniauth-oauth2 (1.8.0)
+      oauth2 (>= 1.4, < 3)
+      omniauth (~> 2.0)
+    rack (3.1.6)
+    rack-protection (4.0.0)
+      base64 (>= 0.1.0)
+      rack (>= 3.0.0, < 4)
+    rack-session (2.0.0)
+      rack (>= 3.0.0)
+    ruby2_keywords (0.0.5)
+    sinatra (4.0.0)
+      mustermann (~> 3.0)
+      rack (>= 3.0.0, < 4)
+      rack-protection (= 4.0.0)
+      rack-session (>= 2.0.0, < 3)
       tilt (~> 2.0)
-    sinatra-contrib (2.0.8.1)
-      backports (>= 2.8.2)
-      multi_json
-      mustermann (~> 1.0)
-      rack-protection (= 2.0.8.1)
-      sinatra (= 2.0.8.1)
+    sinatra-contrib (4.0.0)
+      multi_json (>= 0.0.2)
+      mustermann (~> 3.0)
+      rack-protection (= 4.0.0)
+      sinatra (= 4.0.0)
       tilt (~> 2.0)
     sinatra-reloader (1.0)
       sinatra-contrib
-    tilt (2.0.10)
+    snaky_hash (2.0.1)
+      hashie
+      version_gem (~> 1.1, >= 1.1.1)
+    tilt (2.4.0)
+    uri (0.13.0)
+    version_gem (1.1.4)
 
 PLATFORMS
   ruby
@@ -60,4 +75,4 @@ DEPENDENCIES
   sinatra-reloader
 
 BUNDLED WITH
-   1.17.3
+   2.5.14

example/config.ru

@@ -2,7 +2,7 @@ require 'bundler/setup'
 require 'omniauth-facebook'
 require './app.rb'
 
-use Rack::Session::Cookie, secret: 'abc123'
+use Rack::Session::Cookie, secret: 'rqt2iy17g0vpkouu995r598671cihpae9mritav0yctevwqhprpr71oumzlv5c3z'
 
 use OmniAuth::Builder do
   provider :facebook, ENV['FACEBOOK_APP_ID'], ENV['FACEBOOK_APP_SECRET']