Changed badge style

Author: rkbalgi

README.md

@@ -2,7 +2,7 @@
 [![codecov](https://codecov.io/gh/rkbalgi/isosim/branch/master/graph/badge.svg)](https://codecov.io/gh/rkbalgi/isosim)
 [![GoDev](https://img.shields.io/badge/go.dev-reference-007d9c?logo=go&logoColor=white&style=flat-square)](https://pkg.go.dev/github.com/rkbalgi/isosim?tab=doc)
 ![build](https://github.com/rkbalgi/isosim/workflows/build/badge.svg)
-![GitHub release (latest by date including pre-releases)](https://img.shields.io/github/v/release/rkbalgi/isosim?include_prereleases&style=plastic)
+![GitHub release (latest by date including pre-releases)](https://img.shields.io/github/v/release/rkbalgi/isosim?include_prereleases&style=flat)
 
 # ISO WebSim
 A very short screencast - [https://youtu.be/vSRZ_nzU-Jg](https://youtu.be/vSRZ_nzU-Jg)