Shift required_ruby_version to v3.1.4

Breaking change:
2.7x was end of support 31 Mar 2023
We'll run into dependency issues (expectations having moved up) if we
don't upgrade.

Let's move the testing to target the 3x serise, but enfore 3 as a new
minimum.

.github/workflows/publish.yaml

@@ -20,7 +20,7 @@ jobs:
 
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: '3'
+          ruby-version: "3"
 
       - name: Check if new version to release
         id: gem_version
@@ -40,7 +40,7 @@ jobs:
     name: Publish Ruby Gem
     environment: rubygems
     permissions:
-      contents: write  # needed to be able to tag the release
+      contents: write # needed to be able to tag the release
     runs-on: ubuntu-latest
     needs: pre
     if: ${{ needs.pre.outputs.go == 'true' }}
@@ -50,12 +50,12 @@ jobs:
 
       - uses: actions/setup-node@v3
         with:
-          node-version-file: '.nvmrc'
-          cache: 'npm'
+          node-version-file: ".nvmrc"
+          cache: "npm"
 
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: '3'
+          ruby-version: "3"
           bundler-cache: true
 
       - name: Publish

.github/workflows/test.yaml

@@ -9,15 +9,15 @@ jobs:
 
     strategy:
       matrix:
-        ruby: ['2.7', '3.2']
+        ruby: ["3.1", "3.2", "3.3"]
 
     steps:
       - uses: actions/checkout@v3
 
       - uses: actions/setup-node@v3
         with:
-          node-version-file: '.nvmrc'
-          cache: 'npm'
+          node-version-file: ".nvmrc"
+          cache: "npm"
 
       - uses: ruby/setup-ruby@v1
         with:

govuk_tech_docs.gemspec

@@ -33,7 +33,7 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = %w[lib]
 
-  spec.required_ruby_version = ">= 2.7.0"
+  spec.required_ruby_version = ">= 3.1.4"
 
   spec.add_dependency "autoprefixer-rails", "~> 10.2"
   spec.add_dependency "chronic", "~> 0.10.2"