Bump govuk_tech_docs in /tech-docs in the minor group (#705)

Bumps the minor group in /tech-docs with 1 update: [govuk_tech_docs](https://github.com/alphagov/tech-docs-gem).


Updates `govuk_tech_docs` from 4.1.1 to 4.2.0
- [Release notes](https://github.com/alphagov/tech-docs-gem/releases)
- [Changelog](https://github.com/alphagov/tech-docs-gem/blob/main/CHANGELOG.md)
- [Commits](alphagov/tech-docs-gem@v4.1.1...v4.2.0)

---
updated-dependencies:
- dependency-name: govuk_tech_docs
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

tech-docs/Gemfile.lock

@@ -1,7 +1,7 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    activesupport (7.0.8.6)
+    activesupport (7.0.8.7)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 1.6, < 2)
       minitest (>= 5.1)
@@ -12,7 +12,7 @@ GEM
       execjs (~> 2)
     backports (3.25.0)
     base64 (0.2.0)
-    bigdecimal (3.1.8)
+    bigdecimal (3.1.9)
     chronic (0.10.2)
     chunky_png (1.4.0)
     coffee-script (2.4.1)
@@ -34,29 +34,30 @@ GEM
       sass (>= 3.2, < 3.5)
     concurrent-ruby (1.3.4)
     contracts (0.16.1)
-    csv (3.3.0)
-    dotenv (3.1.4)
+    csv (3.3.2)
+    dotenv (3.1.7)
     em-websocket (0.5.3)
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0)
     erubis (2.7.0)
     eventmachine (1.2.7)
     execjs (2.10.0)
     fast_blank (1.0.1)
-    fastimage (2.3.1)
-    ffi (1.17.0-arm64-darwin)
-    ffi (1.17.0-x86_64-linux-gnu)
-    google-protobuf (4.28.3-arm64-darwin)
+    fastimage (2.4.0)
+    ffi (1.17.1-arm64-darwin)
+    ffi (1.17.1-x86_64-linux-gnu)
+    google-protobuf (4.29.3-arm64-darwin)
       bigdecimal
       rake (>= 13)
-    google-protobuf (4.28.3-x86_64-linux)
+    google-protobuf (4.29.3-x86_64-linux)
       bigdecimal
       rake (>= 13)
-    govuk_tech_docs (4.1.1)
+    govuk_tech_docs (4.2.0)
       autoprefixer-rails (~> 10.2)
       base64
       bigdecimal
       chronic (~> 0.10.2)
+      concurrent-ruby (= 1.3.4)
       csv
       haml (~> 6.0)
       middleman (~> 4.0)
@@ -141,12 +142,12 @@ GEM
     middleman-syntax (3.4.0)
       middleman-core (>= 3.2)
       rouge (~> 3.2)
-    minitest (5.25.2)
+    minitest (5.25.4)
     multi_json (1.15.0)
     mutex_m (0.3.0)
-    nokogiri (1.16.7-arm64-darwin)
+    nokogiri (1.18.3-arm64-darwin)
       racc (~> 1.4)
-    nokogiri (1.16.7-x86_64-linux)
+    nokogiri (1.18.3-x86_64-linux-gnu)
       racc (~> 1.4)
     openapi3_parser (0.9.2)
       commonmarker (~> 0.17)
@@ -159,21 +160,21 @@ GEM
     parslet (2.0.0)
     public_suffix (6.0.1)
     racc (1.8.1)
-    rack (2.2.10)
+    rack (2.2.11)
     rack-livereload (0.3.17)
       rack
     rake (13.2.1)
     rb-fsevent (0.11.2)
     rb-inotify (0.11.1)
       ffi (~> 1.0)
-    redcarpet (3.6.0)
-    rexml (3.3.9)
+    redcarpet (3.6.1)
+    rexml (3.4.1)
     rouge (3.30.0)
     sass (3.4.25)
-    sass-embedded (1.81.0-arm64-darwin)
-      google-protobuf (~> 4.28)
-    sass-embedded (1.81.0-x86_64-linux-gnu)
-      google-protobuf (~> 4.28)
+    sass-embedded (1.85.1-arm64-darwin)
+      google-protobuf (~> 4.29)
+    sass-embedded (1.85.1-x86_64-linux-gnu)
+      google-protobuf (~> 4.29)
     sassc (2.4.0)
       ffi (~> 1.9)
     sassc-embedded (1.78.0)
@@ -183,7 +184,7 @@ GEM
       concurrent-ruby (~> 1.0)
       rack (>= 2.2.4, < 4)
     temple (0.10.3)
-    terser (1.2.4)
+    terser (1.2.5)
       execjs (>= 0.3.0, < 3)
     thor (1.2.2)
     tilt (2.0.11)
@@ -193,7 +194,7 @@ GEM
       concurrent-ruby (~> 1.0)
     uglifier (3.2.0)
       execjs (>= 0.3.0, < 3)
-    webrick (1.9.0)
+    webrick (1.9.1)
 
 PLATFORMS
   arm64-darwin-23