Add missing changelog-generator configuration

ci/config/changelog-generator.yml

@@ -0,0 +1,17 @@
+changelog:
+  repository: spring-io/spring-asciidoctor-extensions
+  sections:
+    - title: ":star: New Features"
+      labels:
+        - "type: enhancement"
+    - title: ":lady_beetle: Bug Fixes"
+      labels:
+        - "type: bug"
+        - "type: regression"
+    - title: ":notebook_with_decorative_cover: Documentation"
+      labels:
+        - "type: documentation"
+    - title: ":hammer: Dependency Upgrades"
+      sort: "title"
+      labels:
+        - "type: dependency-upgrade"