Fixup parent POM version number

Author: philwebb

spring-boot-samples/spring-boot-sample-secure-oauth2-actuator/pom.xml

@@ -5,7 +5,7 @@
 <!-- Your own application should inherit from spring-boot-starter-parent -->
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-samples</artifactId>
-<version>1.5.0.BUILD-SNAPSHOT</version>
+<version>2.0.0.BUILD-SNAPSHOT</version>
 </parent>
 <artifactId>spring-boot-sample-secure-oauth2-actuator</artifactId>
 <name>spring-boot-sample-secure-oauth2-actuator</name>