prepare 0.2.6 snapshot, update readme

Author: wing328

README.md

@@ -1,6 +1,6 @@
 # jackson-databind-nullable
 
-[![Build Status](https://travis-ci.org/OpenAPITools/jackson-databind-nullable.svg?branch=master)](https://travis-ci.org/OpenAPITools/jackson-databind-nullable)
+[![Build Status](https://api.travis-ci.com/OpenAPITools/jackson-databind-nullable.svg?branch=master&status=passed)](https://app.travis-ci.com/github/OpenAPITools/jackson-databind-nullable)
 
 This module provides a `JsonNullable` wrapper class and a Jackson module to serialize/deserialize it.
 The `JsonNullable` wrapper shall be used to wrap Java bean fields for which it is important to distinguish between an explicit `"null"` and the field not being present.

pom.xml

@@ -10,7 +10,7 @@
     <packaging>jar</packaging>
     <name>JsonNullable Jackson module</name>
     <description>JsonNullable wrapper class and Jackson module to support fields with meaningful null values.</description>
-    <version>0.2.5-SNAPSHOT</version>
+    <version>0.2.6-SNAPSHOT</version>
 
     <url>https://github.com/OpenAPITools/jackson-databind-nullable</url>
     <scm>