Update gems for ruby 3.1.2 & Heroku-22 stack

Replaced RedisToGo add-on with Heroku Data for Redis due to EOL.
Updated gems for ruby 3.1.2 and Heroku-22 stack compatibility

Gemfile.lock

@@ -1,71 +1,69 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    activesupport (5.2.4.3)
+    activesupport (7.0.3.1)
       concurrent-ruby (~> 1.0, >= 1.0.2)
-      i18n (>= 0.7, < 2)
-      minitest (~> 5.1)
-      tzinfo (~> 1.1)
-    backports (3.11.4)
-    builder (3.2.3)
-    concurrent-ruby (1.1.8)
-    daemons (1.2.6)
-    diff-lcs (1.3)
+      i18n (>= 1.6, < 2)
+      minitest (>= 5.1)
+      tzinfo (~> 2.0)
+    builder (3.2.4)
+    concurrent-ruby (1.1.10)
+    daemons (1.4.1)
+    diff-lcs (1.5.0)
     eventmachine (1.2.7)
-    haml (5.0.4)
+    haml (5.2.2)
       temple (>= 0.8.0)
       tilt
-    i18n (1.8.9)
+    i18n (1.12.0)
       concurrent-ruby (~> 1.0)
-    mini_portile2 (2.6.1)
-    minitest (5.14.4)
-    multi_json (1.13.1)
-    mustermann (1.0.3)
-    nokogiri (1.12.5)
-      mini_portile2 (~> 2.6.1)
+    mini_portile2 (2.8.0)
+    minitest (5.16.2)
+    multi_json (1.15.0)
+    mustermann (2.0.2)
+      ruby2_keywords (~> 0.0.1)
+    nokogiri (1.13.8)
+      mini_portile2 (~> 2.8.0)
       racc (~> 1.4)
-    prometheus-client (2.1.0)
-    racc (1.5.2)
-    rack (2.2.3)
-    rack-protection (2.0.4)
+    prometheus-client (4.0.0)
+    racc (1.6.0)
+    rack (2.2.4)
+    rack-protection (2.2.2)
       rack
     redcarpet (3.5.1)
-    redis (4.0.3)
-    rspec (3.8.0)
-      rspec-core (~> 3.8.0)
-      rspec-expectations (~> 3.8.0)
-      rspec-mocks (~> 3.8.0)
-    rspec-core (3.8.1)
-      rspec-support (~> 3.8.0)
-    rspec-expectations (3.8.4)
+    redis (4.7.1)
+    rspec (3.11.0)
+      rspec-core (~> 3.11.0)
+      rspec-expectations (~> 3.11.0)
+      rspec-mocks (~> 3.11.0)
+    rspec-core (3.11.0)
+      rspec-support (~> 3.11.0)
+    rspec-expectations (3.11.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.8.0)
-    rspec-mocks (3.8.1)
+      rspec-support (~> 3.11.0)
+    rspec-mocks (3.11.1)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.8.0)
-    rspec-support (3.8.2)
-    sinatra (2.0.4)
-      mustermann (~> 1.0)
-      rack (~> 2.0)
-      rack-protection (= 2.0.4)
+      rspec-support (~> 3.11.0)
+    rspec-support (3.11.0)
+    ruby2_keywords (0.0.5)
+    sinatra (2.2.2)
+      mustermann (~> 2.0)
+      rack (~> 2.2)
+      rack-protection (= 2.2.2)
       tilt (~> 2.0)
-    sinatra-contrib (2.0.4)
-      activesupport (>= 4.0.0)
-      backports (>= 2.8.2)
+    sinatra-contrib (2.2.2)
       multi_json
-      mustermann (~> 1.0)
-      rack-protection (= 2.0.4)
-      sinatra (= 2.0.4)
-      tilt (>= 1.3, < 3)
-    temple (0.8.0)
-    thin (1.8.0)
+      mustermann (~> 2.0)
+      rack-protection (= 2.2.2)
+      sinatra (= 2.2.2)
+      tilt (~> 2.0)
+    temple (0.8.2)
+    thin (1.8.1)
       daemons (~> 1.0, >= 1.0.9)
       eventmachine (~> 1.0, >= 1.0.4)
       rack (>= 1, < 3)
-    thread_safe (0.3.6)
-    tilt (2.0.9)
-    tzinfo (1.2.9)
-      thread_safe (~> 0.1)
+    tilt (2.0.11)
+    tzinfo (2.0.5)
+      concurrent-ruby (~> 1.0)
 
 PLATFORMS
   ruby

README.md

@@ -78,7 +78,7 @@ make FA_COOKIE="b\=...\;a\=..." deploy_bypass
 
 ## Deploying - Heroku
 
-This application can be run on Heroku, just add an instance of 'Redis To Go' for caching.
+This application can be run on Heroku, just add an instance of [`Heroku Data for Redis®`](https://elements.heroku.com/addons/heroku-redis) for caching.
 Rather than uploading `settings.yml`, set the environment variable `FA_COOKIE`
 to the generated cookie you gathered from FA.