docs(readme): add Greenkeeper badge

greenkeeper[bot] · greenkeeper[bot] · commit d7bda1f860e0 · 2019-03-14T22:19:23.000Z
diff --git a/README.md b/README.md
@@ -1,4 +1,4 @@
-# nut-tree/secrets [![Build Status](https://travis-ci.com/nut-tree/secrets.svg?branch=master)](https://travis-ci.com/nut-tree/secrets) [![SonarCloud badge](https://sonarcloud.io/api/project_badges/measure?project=nut-tree_secrets&metric=alert_status)](https://sonarcloud.io/dashboard?id=nut-tree_secrets) [![SonarCloud Coverage](https://sonarcloud.io/api/project_badges/measure?project=nut-tree_secrets&metric=coverage)](https://sonarcloud.io/component_measures?id=nut-tree_secrets&metric=coverage)
+# nut-tree/secrets [![Build Status](https://travis-ci.com/nut-tree/secrets.svg?branch=master)](https://travis-ci.com/nut-tree/secrets) [![SonarCloud badge](https://sonarcloud.io/api/project_badges/measure?project=nut-tree_secrets&metric=alert_status)](https://sonarcloud.io/dashboard?id=nut-tree_secrets) [![SonarCloud Coverage](https://sonarcloud.io/api/project_badges/measure?project=nut-tree_secrets&metric=coverage)](https://sonarcloud.io/component_measures?id=nut-tree_secrets&metric=coverage) [![Greenkeeper badge](https://badges.greenkeeper.io/nut-tree/secrets.svg)](https://greenkeeper.io/)
 
 ## A utility package to handle secrets in test cases.
 

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`1`		`-# nut-tree/secrets [![Build Status](https://travis-ci.com/nut-tree/secrets.svg?branch=master)](https://travis-ci.com/nut-tree/secrets) [![SonarCloud badge](https://sonarcloud.io/api/project_badges/measure?project=nut-tree_secrets&metric=alert_status)](https://sonarcloud.io/dashboard?id=nut-tree_secrets) [![SonarCloud Coverage](https://sonarcloud.io/api/project_badges/measure?project=nut-tree_secrets&metric=coverage)](https://sonarcloud.io/component_measures?id=nut-tree_secrets&metric=coverage)`
	`1`	+# nut-tree/secrets [![Build Status](https://travis-ci.com/nut-tree/secrets.svg?branch=master)](https://travis-ci.com/nut-tree/secrets) [![SonarCloud badge](https://sonarcloud.io/api/project_badges/measure?project=nut-tree_secrets&metric=alert_status)](https://sonarcloud.io/dashboard?id=nut-tree_secrets) [![SonarCloud Coverage](https://sonarcloud.io/api/project_badges/measure?project=nut-tree_secrets&metric=coverage)](https://sonarcloud.io/component_measures?id=nut-tree_secrets&metric=coverage) [![Greenkeeper badge](https://badges.greenkeeper.io/nut-tree/secrets.svg)](https://greenkeeper.io/)
`2`	`2`
`3`	`3`	`## A utility package to handle secrets in test cases.`
`4`	`4`