doc: Update staging branch list and clarify publishing rules

Author: yongruilin

contributors/devel/sig-architecture/staging.md

@@ -6,20 +6,20 @@ We publish the staging repos using the [publishing bot](https://git.k8s.io/publi
 
 The list of staging repositories currently published is available in [staging/README.md inside of the k8s.io/kubernetes repository](https://git.k8s.io/kubernetes/staging/README.md).
 
-At the time of this writing, the list of published branches includes:
+At the time of this writing, based on [publishing rule](https://github.com/kubernetes/kubernetes/blob/9cf4f912451009296a50f267d47b484f77ce05e4/staging/publishing/rules.yaml), the list of published branches includes:
 
 - master,
-- release-1.14 / release-11.0,
-- release-1.15 / release-12.0,
-- release-1.16 / release-13.0,
-- and release-1.17 / release-14.0
+- release-1.28
+- release-1.29
+- release-1.30
+- release-1.31
 
-Kubernetes tags (e.g., `v1.17.0-beta.2`) are also applied automatically to the published repositories, prefixed with `kubernetes-`.
+Kubernetes tags (e.g., `v1.30.0-beta.0`) are also applied automatically to the published repositories, prefixed with `kubernetes-`.
 From `v1.17.0` Kubernetes release, matching semver `v0.x.y` tags are also created for each `v1.x.y` Kubernetes tag.
 
-For example, if you check out the `kubernetes-1.17.0` or the `v0.17.0` tag in
+For example, if you check out the `kubernetes-1.30.0` or the `v0.30.0` tag in
 a published repo, the code you get is exactly the same as if you check out the
-`v1.17.0` tag in Kubernetes, and change directory to `staging/src/k8s.io/<repo-name>`.
+`v1.30.0` tag in Kubernetes, and change directory to `staging/src/k8s.io/<repo-name>`.
 
 It is recommend to use the semver `v0.x.y` tags for a seamless experience
 with go modules.