Update sanitize to v6.0.0

This requires Nokogiri v1.12 and eliminates Nokogumbo as Nokogiri
includes both.

Gemfile

@@ -264,7 +264,7 @@ gem 'ruby-fogbugz', '~> 0.2.1'
 gem 'kubeclient', '~> 4.9.2'
 
 # Sanitize user input
-gem 'sanitize', '~> 5.2.1'
+gem 'sanitize', '~> 6.0'
 gem 'babosa', '~> 1.0.4'
 
 # Sanitizes SVG input

Gemfile.lock

@@ -795,8 +795,6 @@ GEM
     nokogiri (1.12.5)
       mini_portile2 (~> 2.6.1)
       racc (~> 1.4)
-    nokogumbo (2.0.2)
-      nokogiri (~> 1.8, >= 1.8.4)
     notiffany (0.1.3)
       nenv (~> 0.1)
       shellany (~> 0.0)
@@ -1144,10 +1142,9 @@ GEM
     safe_yaml (1.0.4)
     safety_net_attestation (0.4.0)
       jwt (~> 2.0)
-    sanitize (5.2.1)
+    sanitize (6.0.0)
       crass (~> 1.0.2)
-      nokogiri (>= 1.8.0)
-      nokogumbo (~> 2.0)
+      nokogiri (>= 1.12.0)
     sass (3.5.5)
       sass-listen (~> 4.0.0)
     sass-listen (4.0.0)
@@ -1624,7 +1621,7 @@ DEPENDENCIES
   ruby_parser (~> 3.15)
   rubyzip (~> 2.0.0)
   rugged (~> 1.2)
-  sanitize (~> 5.2.1)
+  sanitize (~> 6.0)
   sassc-rails (~> 2.1.0)
   sd_notify (~> 0.1.0)
   seed-fu (~> 2.3.7)

lib/banzai/filter/base_sanitization_filter.rb

@@ -42,7 +42,7 @@ module Banzai
           # Allow any protocol in `a` elements
           # and then remove links with unsafe protocols
           allowlist[:protocols].delete('a')
-          allowlist[:transformers].push(self.class.method(:remove_unsafe_links))
+          allowlist[:transformers].push(self.class.method(:sanitize_unsafe_links))
 
           # Remove `rel` attribute from `a` elements
           allowlist[:transformers].push(self.class.remove_rel)

lib/gitlab/utils/sanitize_node_link.rb

@@ -8,6 +8,12 @@ module Gitlab
       UNSAFE_PROTOCOLS  = %w(data javascript vbscript).freeze
       ATTRS_TO_SANITIZE = %w(href src data-src data-canonical-src).freeze
 
+      # sanitize 6.0 requires only a context argument. Do not add any default
+      # arguments to this method.
+      def sanitize_unsafe_links(env)
+        remove_unsafe_links(env)
+      end
+
       def remove_unsafe_links(env, remove_invalid_links: true)
         node = env[:node]