Remove experimental lifecycle badge from README

Removed the experimental lifecycle badge from the README.

Author: n8thangreen

README.md

@@ -7,8 +7,6 @@ outstandR: *Out*come regression *stand*ardisation
 <!-- badges: start -->
 
 [![R-CMD-check](https://github.com/StatisticsHealthEconomics/outstandR/actions/workflows/R-CMD-check.yaml/badge.svg)](https://github.com/StatisticsHealthEconomics/outstandR/actions/workflows/R-CMD-check.yaml)
-[![Lifecycle:
-experimental](https://img.shields.io/badge/lifecycle-experimental-orange.svg)](https://lifecycle.r-lib.org/articles/stages.html#experimental)
 [![License: GPL
 v3](https://img.shields.io/badge/License-GPLv3-blue.svg)](https://www.gnu.org/licenses/gpl-3.0)
 [![outstandR status