Add Stack Overflow badges in README (also remove LICENSE badge)

Author: augustoproiete

README.md

@@ -1,4 +1,4 @@
-# Serilog.Enrichers.ExcelDna [![NuGet Version](http://img.shields.io/nuget/v/Serilog.Enrichers.ExcelDna.svg?style=flat)](https://www.nuget.org/packages/Serilog.Enrichers.ExcelDna/) [![License](https://img.shields.io/github/license/augustoproiete/serilog-enrichers-exceldna.svg)](LICENSE)
+# Serilog.Enrichers.ExcelDna [![NuGet Version](http://img.shields.io/nuget/v/Serilog.Enrichers.ExcelDna.svg?style=flat)](https://www.nuget.org/packages/Serilog.Enrichers.ExcelDna/) [![Stack Overflow](https://img.shields.io/badge/stack%20overflow-serilog-orange.svg)](http://stackoverflow.com/questions/tagged/serilog) [![Stack Overflow](https://img.shields.io/badge/stack%20overflow-excel--dna-orange.svg)](http://stackoverflow.com/questions/tagged/excel-dna)
 
 Enriches [Serilog](https://serilog.net) events with information from your [Excel-DNA](https://excel-dna.net) Add-in.