update Helm documentation

Author: github-actions[bot]

charts/ecowitt-exporter/README.md

@@ -1,6 +1,6 @@
 # ecowitt-exporter
 
-![Version: 0.8.0](https://img.shields.io/badge/Version-0.8.0-informational?style=flat-square) ![Type: application](https://img.shields.io/badge/Type-application-informational?style=flat-square) ![AppVersion: 0.8.0](https://img.shields.io/badge/AppVersion-0.8.0-informational?style=flat-square)
+![Version: 0.8.1](https://img.shields.io/badge/Version-0.8.1-informational?style=flat-square) ![Type: application](https://img.shields.io/badge/Type-application-informational?style=flat-square) ![AppVersion: 0.8.1](https://img.shields.io/badge/AppVersion-0.8.1-informational?style=flat-square)
 
 A Prometheus & InfluxDB exporter for Ecowitt weather stations