Use DSv5 through Tech Docs Gem v.4.0.0

With this change, we are updating the Pay Tech Docs so that they use the new
version of the Design System (v.5) through the brand new version of Tech Docs
Gem[1].

Further information in Jira[2].

[1]
alphagov/tech-docs-gem#375

[2]
https://payments-platform.atlassian.net/browse/PP-13122

Gemfile

@@ -1,5 +1,5 @@
 source 'https://rubygems.org'
 
-gem 'govuk_tech_docs', '~> 3.5.0'
-gem 'haml', '~> 5.2', '>= 5.2.2'
+gem 'govuk_tech_docs', '~> 4.0'
+gem "haml", "~> 6.0"
 gem 'html-proofer'

Gemfile.lock

@@ -1,16 +1,18 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    activesupport (7.0.8.1)
+    activesupport (7.0.8.5)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 1.6, < 2)
       minitest (>= 5.1)
       tzinfo (~> 2.0)
     addressable (2.8.4)
       public_suffix (>= 2.0.2, < 6.0)
-    autoprefixer-rails (10.4.16.0)
+    autoprefixer-rails (10.4.19.0)
       execjs (~> 2)
-    backports (3.24.1)
+    backports (3.25.0)
+    base64 (0.2.0)
+    bigdecimal (3.1.8)
     chronic (0.10.2)
     chunky_png (1.4.0)
     coffee-script (2.4.1)
@@ -30,36 +32,47 @@ GEM
       sass (>= 3.3.0, < 3.5)
     compass-import-once (1.0.5)
       sass (>= 3.2, < 3.5)
-    concurrent-ruby (1.2.3)
+    concurrent-ruby (1.3.4)
     contracts (0.16.1)
-    dotenv (3.1.0)
+    csv (3.3.0)
+    dotenv (3.1.4)
     em-websocket (0.5.3)
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0)
     erubis (2.7.0)
     ethon (0.15.0)
       ffi (>= 1.15.0)
     eventmachine (1.2.7)
-    execjs (2.9.1)
+    execjs (2.10.0)
     fast_blank (1.0.1)
-    fastimage (2.3.0)
+    fastimage (2.3.1)
     ffi (1.15.5)
-    govuk_tech_docs (3.5.0)
+    google-protobuf (4.28.2)
+      bigdecimal
+      rake (>= 13)
+    govuk_tech_docs (4.0.0)
       autoprefixer-rails (~> 10.2)
+      base64
+      bigdecimal
       chronic (~> 0.10.2)
-      haml (< 6.0.0)
+      csv
+      haml (~> 6.0)
       middleman (~> 4.0)
-      middleman-autoprefixer (~> 2.10.0)
-      middleman-compass (>= 4.0.0)
+      middleman-autoprefixer (~> 2.10)
+      middleman-compass (~> 4.0)
       middleman-livereload
       middleman-search-gds
       middleman-sprockets (~> 4.0.0)
-      middleman-syntax (~> 3.2.0)
+      middleman-syntax (~> 3.4)
+      mutex_m
       nokogiri
       openapi3_parser (~> 0.9.0)
-      redcarpet (~> 3.5.1)
-    haml (5.2.2)
-      temple (>= 0.8.0)
+      redcarpet (~> 3.6)
+      sassc-embedded (~> 1.78.0)
+      terser (~> 1.2.3)
+    haml (6.3.0)
+      temple (>= 0.8.2)
+      thor
       tilt
     hamster (3.0.0)
       concurrent-ruby (~> 1.0)
@@ -132,12 +145,13 @@ GEM
     middleman-sprockets (4.0.0)
       middleman-core (~> 4.0)
       sprockets (>= 3.0)
-    middleman-syntax (3.2.0)
+    middleman-syntax (3.4.0)
       middleman-core (>= 3.2)
       rouge (~> 3.2)
     mini_portile2 (2.8.6)
-    minitest (5.22.2)
+    minitest (5.25.1)
     multi_json (1.15.0)
+    mutex_m (0.2.0)
     nokogiri (1.16.5)
       mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
@@ -152,26 +166,32 @@ GEM
     parslet (2.0.0)
     public_suffix (5.0.1)
     racc (1.7.3)
-    rack (2.2.8.1)
+    rack (2.2.10)
     rack-livereload (0.3.17)
       rack
     rainbow (3.1.1)
+    rake (13.2.1)
     rb-fsevent (0.11.2)
-    rb-inotify (0.10.1)
+    rb-inotify (0.11.1)
       ffi (~> 1.0)
-    redcarpet (3.5.1)
-    rexml (3.3.6)
-      strscan
+    redcarpet (3.6.0)
+    rexml (3.3.8)
     rouge (3.30.0)
     sass (3.4.25)
+    sass-embedded (1.80.3)
+      google-protobuf (~> 4.28)
+      rake (>= 13)
     sassc (2.4.0)
       ffi (~> 1.9)
+    sassc-embedded (1.78.0)
+      sass-embedded (~> 1.78)
     servolux (0.13.0)
     sprockets (4.2.1)
       concurrent-ruby (~> 1.0)
       rack (>= 2.2.4, < 4)
-    strscan (3.1.0)
-    temple (0.10.2)
+    temple (0.10.3)
+    terser (1.2.4)
+      execjs (>= 0.3.0, < 3)
     thor (1.2.2)
     tilt (2.0.11)
     toml (0.3.0)
@@ -182,15 +202,15 @@ GEM
       concurrent-ruby (~> 1.0)
     uglifier (3.2.0)
       execjs (>= 0.3.0, < 3)
-    webrick (1.8.1)
+    webrick (1.8.2)
     yell (2.2.2)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
-  govuk_tech_docs (~> 3.5.0)
-  haml (~> 5.2, >= 5.2.2)
+  govuk_tech_docs (~> 4.0)
+  haml (~> 6.0)
   html-proofer
 
 BUNDLED WITH

source/javascripts/govuk_frontend.js

@@ -0,0 +1 @@
+//= require govuk_frontend_all