Remove test coverage badge from README

Removed test coverage badge from README.

Author: kkbrum

README.Rmd

@@ -17,7 +17,6 @@ knitr::opts_chunk$set(
 
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-[![test-coverage](https://github.com/kkbrum/optrefine/actions/workflows/test-coverage.yaml/badge.svg)](https://github.com/kkbrum/optrefine/actions/workflows/test-coverage.yaml)
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 The goal of optrefine is to split existing strata (or none) into more refined strata that optimize covariate balance. Most often, propensity score strata are each split into two in order to achieve better covariate balance.