Add display of Linux Foundation (LF) Core Infrastructure Initiative (CII) Best Practices badge

Author: kwwall

README.md

@@ -4,6 +4,7 @@ Enterprise Security API for Java (Legacy)
 [![Build Status](https://travis-ci.org/bkimminich/esapi-java-legacy.svg?branch=master)](https://travis-ci.org/bkimminich/esapi-java-legacy)
 [![Coverage Status](https://coveralls.io/repos/github/bkimminich/esapi-java-legacy/badge.svg?branch=develop)](https://coveralls.io/github/bkimminich/esapi-java-legacy?branch=develop)
 [![Coverity Status](https://scan.coverity.com/projects/8517/badge.svg)](https://scan.coverity.com/projects/bkimminich-esapi-java-legacy)
+[![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/137/badge)](https://bestpractices.coreinfrastructure.org/projects/137)
 
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