Update Gerrit plugin API version to 2.6

Change-Id: I2103a63472a491ba9b23e9880fe7756d91e15705

pom.xml

diff --git a/pom.xml b/pom.xml
index f1df7e1..7071aa8 100644
--- a/pom.xml
+++ b/pom.xml
@@ -25,7 +25,7 @@
   <version>0.1</version>
   <properties>
     <Gerrit-ApiType>plugin</Gerrit-ApiType>
-    <Gerrit-ApiVersion>2.5-SNAPSHOT</Gerrit-ApiVersion>
+    <Gerrit-ApiVersion>2.6-SNAPSHOT</Gerrit-ApiVersion>
   </properties>
 
   <build>