Update to parent pom 18

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1520554 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/pom.xml b/pom.xml
index 633805c..2df1c39 100644
--- a/pom.xml
+++ b/pom.xml
@@ -23,7 +23,7 @@
 	<parent>
 		<groupId>org.apache.sling</groupId>
 		<artifactId>sling</artifactId>
-		<version>17</version>
+		<version>18</version>
 		<relativePath>../../parent/pom.xml</relativePath>
 	</parent>