docs: add status badge for the periodic cronjob

Additionally, rename it to a more fitting name.

Author: rexagod

.github/workflows/cron.yml renamed to .github/workflows/govulncheck.yml

@@ -1,4 +1,4 @@
-name: cron
+name: govulncheck
 
 on:
   schedule:

README.md

@@ -1,7 +1,9 @@
 # Overview
 
 [![Build Status](https://github.com/kubernetes/kube-state-metrics/workflows/continuous-integration/badge.svg)](https://github.com/kubernetes/kube-state-metrics/actions)
-[![Go Report Card](https://goreportcard.com/badge/github.com/kubernetes/kube-state-metrics)](https://goreportcard.com/report/github.com/kubernetes/kube-state-metrics) [![GoDoc](https://godoc.org/github.com/kubernetes/kube-state-metrics?status.svg)](https://godoc.org/github.com/kubernetes/kube-state-metrics)
+[![Go Report Card](https://goreportcard.com/badge/github.com/kubernetes/kube-state-metrics)](https://goreportcard.com/report/github.com/kubernetes/kube-state-metrics)
+[![Go Reference](https://pkg.go.dev/badge/github.com/kubernetes/kube-state-metrics.svg)](https://pkg.go.dev/github.com/kubernetes/kube-state-metrics)
+[![govulncheck](https://github.com/kubernetes/kube-state-metrics/actions/workflows/govulncheck.yml/badge.svg)](https://github.com/kubernetes/kube-state-metrics/actions/workflows/govulncheck.yml)
 
 kube-state-metrics (KSM) is a simple service that listens to the Kubernetes API
 server and generates metrics about the state of the objects. (See examples in