minor: fixup build badge links

acmorrow · acmorrow · commit dbd447fad091 · 2017-11-08T13:20:34.000-05:00
diff --git a/README.md b/README.md
@@ -1,4 +1,4 @@
-# MongoDB C++ Driver [![Build Status](https://travis-ci.org/mongodb/mongo-cxx-driver.svg?branch=3.1-dev)](https://travis-ci.org/mongodb/mongo-cxx-driver)[![Windows Build Status](https://ci.appveyor.com/api/projects/status/w95xuowdjpr0img1/branch/3.1-dev?svg=true)](https://ci.appveyor.com/project/markbenvenuto/mongo-cxx-driver)
+# MongoDB C++ Driver [![Evergreen Build Status](https://evergreen.mongodb.com/static/img/favicon.ico)](https://evergreen.mongodb.com/waterfall/cxx-driver-stable)[![Travis Build Status](https://travis-ci.org/mongodb/mongo-cxx-driver.svg?branch=releases%2Fv3.1)](https://travis-ci.org/mongodb/mongo-cxx-driver)
 
 Welcome to the MongoDB C++ Driver!
 

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`@@ -1,4 +1,4 @@`
`1`		`-# MongoDB C++ Driver [![Build Status](https://travis-ci.org/mongodb/mongo-cxx-driver.svg?branch=3.1-dev)](https://travis-ci.org/mongodb/mongo-cxx-driver)[![Windows Build Status](https://ci.appveyor.com/api/projects/status/w95xuowdjpr0img1/branch/3.1-dev?svg=true)](https://ci.appveyor.com/project/markbenvenuto/mongo-cxx-driver)`
	`1`	`+# MongoDB C++ Driver [![Evergreen Build Status](https://evergreen.mongodb.com/static/img/favicon.ico)](https://evergreen.mongodb.com/waterfall/cxx-driver-stable)[![Travis Build Status](https://travis-ci.org/mongodb/mongo-cxx-driver.svg?branch=releases%2Fv3.1)](https://travis-ci.org/mongodb/mongo-cxx-driver)`
`2`	`2`
`3`	`3`	`Welcome to the MongoDB C++ Driver!`
`4`	`4`