[releng] Exclude spring-integration from dependabot updates

Spring 6 needs Java 17+.

Author: tomaswolf

.github/dependabot.yml

@@ -27,6 +27,8 @@ updates:
         versions: [">= 6.0.0"]
       - dependency-name: "org.springframework:spring-framework-bom"
         versions: [">= 6.0.0"]
+      - dependency-name: "org.springframework.integration:spring-integration-bom"
+        versions: [">= 6.0.0"]
       - dependency-name: "org.eclipse.jgit:*"
         versions: [ ">= 6.0.0" ]
       - dependency-name: "org.mockito:*"