Update CI parameters for 2.5.x branch

Author: snicoll

ci/parameters.yml

@@ -6,7 +6,7 @@ github-repo-name: "spring-projects/spring-boot"
 homebrew-tap-repo: "https://github.com/spring-io/homebrew-tap.git"
 docker-hub-organization: "springci"
 artifactory-server: "https://repo.spring.io"
-branch: "main"
+branch: "2.5.x"
 milestone: "2.5.x"
 build-name: "spring-boot"
 concourse-url: "https://ci.spring.io"