feat: next release from main branch is 6.56.0 (#2929)

Author: lqiu96

.github/release-please.yml

@@ -30,3 +30,7 @@ branches:
  bumpMinorPreMajor: true
  handleGHRelease: true
  branch: 6.33.x
+ - releaseType: java-backport
+ bumpMinorPreMajor: true
+ handleGHRelease: true
+ branch: 6.55.x

.github/sync-repo-settings.yaml

@@ -122,6 +122,23 @@ branchProtectionRules:
  - checkstyle
  - compile (8)
  - compile (11)
+ - pattern: 6.55.x
+ isAdminEnforced: true
+ requiredApprovingReviewCount: 1
+ requiresCodeOwnerReviews: true
+ requiresStrictStatusChecks: false
+ requiredStatusCheckContexts:
+ - dependencies (17)
+ - lint
+ - javadoc
+ - units (8)
+ - units (11)
+ - 'Kokoro - Test: Integration'
+ - cla/google
+ - checkstyle
+ - compile (8)
+ - compile (11)
+ - OwlBot Post Processor
 permissionRules:
  - team: yoshi-admins
  permission: admin