updated README compatibility matrix

Author: yliaog

README.md

@@ -97,7 +97,7 @@ supported versions of Kubernetes clusters.
 - [client 25.y.z](https://pypi.org/project/kubernetes/25.3.0/): Kubernetes 1.24 or below (+-), Kubernetes 1.25 (✓), Kubernetes 1.26 or above (+-)
 - [client 26.y.z](https://pypi.org/project/kubernetes/26.1.0/): Kubernetes 1.25 or below (+-), Kubernetes 1.26 (✓), Kubernetes 1.27 or above (+-)
 - [client 27.y.z](https://pypi.org/project/kubernetes/27.2.0/): Kubernetes 1.26 or below (+-), Kubernetes 1.27 (✓), Kubernetes 1.28 or above (+-)
-- [client 28.y.z](https://pypi.org/project/kubernetes/28.1.0/): Kubernetes 1.27 or below (+-), Kubernetes 1.28 (✓), Kubernetes 1.29 or above (+-)
+- [client 28.y.z](https://pypi.org/project/kubernetes/28.1.0b1/): Kubernetes 1.27 or below (+-), Kubernetes 1.28 (✓), Kubernetes 1.29 or above (+-)
 
 > See [here](#homogenizing-the-kubernetes-python-client-versions) for an explanation of why there is no v13-v16 release.