upgrade spring boot to 1.5.1

Author: akirasosa

pom.xml

@@ -12,7 +12,7 @@
     <parent>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
-        <version>1.4.3.RELEASE</version>
+        <version>1.5.1.RELEASE</version>
         <relativePath/>
     </parent>