Use local Kroki instance.

.github/workflows/deploy-docs.yml

@@ -12,6 +12,11 @@ jobs:
   build:
     if: github.repository_owner == 'spring-projects'
     runs-on: ubuntu-latest
+    services:
+      kroki:
+        image: yuzutech/kroki
+        ports:
+          - 4711:8000
     steps:
 
     - name: Checkout

antora-playbook.yml

@@ -22,6 +22,7 @@ asciidoc:
     hide-uri-scheme: '@'
     tabs-sync-option: '@'
     kroki-fetch-diagram: true
+    kroki-server-url: http://localhost:4711
   extensions:
   - '@springio/asciidoctor-extensions'
   - '@asciidoctor/tabs'