ci: Update versions for docs build

Author: XM5jDcsHTyGJtQqlCi

.github/workflows/docs.yml

@@ -11,12 +11,12 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-node@v3
-        with: { node-version: 18 }
+      - uses: actions/setup-node@v4
+        with: { node-version: 20 }
       - uses: ruby/setup-ruby@v1
         with:
           bundler-cache: true
-          ruby-version: '2.7'
+          ruby-version: '3.3'
           working-directory: ./docs
       - run: npm ci
       - run: npm run build

docs/Gemfile

@@ -1,6 +1,3 @@
 source "https://rubygems.org"
 
 gem "github-pages", group: :jekyll_plugins
-
-# https://github.com/jekyll/jekyll/issues/8523
-gem "webrick", "~> 1.7"