fix: status badge brackets

Author: wbollock

README.md

@@ -1,7 +1,7 @@
 # nagios_exporter
 
 [![golangci-lint](https://github.com/wbollock/nagios_exporter/actions/workflows/golangci-lint.yaml/badge.svg)](https://github.com/wbollock/nagios_exporter/actions/workflows/golangci-lint.yaml)
-[![Go Report Card](https://goreportcard.com/badge/github.com/wbollock/nagios_exporter)]
+![Go Report Card](https://goreportcard.com/badge/github.com/wbollock/nagios_exporter)
 
 A Prometheus exporter currently supporting: