add code cov badge

Author: lowlydba

docs/README.md

@@ -1,6 +1,8 @@
 # DBA MultiTool
 
 [![License](https://img.shields.io/github/license/LowlyDBA/dba-multitool?color=blue)][license]
+![Code Coverage](https://raw.githubusercontent.com/lowlydba/dba-multitool/_xml_coverage_reports/data/main/badge.svg)
+
 [![Unit Test (Win SQL Server)](https://github.com/lowlydba/dba-multitool/actions/workflows/sqlserver-unit.yml/badge.svg)](https://github.com/lowlydba/dba-multitool/actions/workflows/sqlserver-unit.yml)
 [![Unit Test (AzureSQL)](https://github.com/lowlydba/dba-multitool/actions/workflows/azuresql-unit.yml/badge.svg)](https://github.com/lowlydba/dba-multitool/actions/workflows/azuresql-unit.yml)
 [![Lint Code](https://github.com/lowlydba/dba-multitool/actions/workflows/lint.yml/badge.svg)](https://github.com/lowlydba/dba-multitool/actions/workflows/lint.yml)