Fix ApprovalCache version

This was wrongly set back to 1 in Id4b3477d9f5.

Change-Id: I822d0b5c948deea532f4694fe5573e57ddf6e0ad
diff --git a/java/com/google/gerrit/server/approval/ApprovalCacheImpl.java b/java/com/google/gerrit/server/approval/ApprovalCacheImpl.java
index 93099eb..a01931c 100644
--- a/java/com/google/gerrit/server/approval/ApprovalCacheImpl.java
+++ b/java/com/google/gerrit/server/approval/ApprovalCacheImpl.java
@@ -49,7 +49,7 @@
                 CACHE_NAME,
                 Cache.PatchSetApprovalsKeyProto.class,
                 Cache.AllPatchSetApprovalsProto.class)
-            .version(1)
+            .version(2)
             .loader(Loader.class)
             .keySerializer(new ProtobufSerializer<>(Cache.PatchSetApprovalsKeyProto.parser()))
             .valueSerializer(new ProtobufSerializer<>(Cache.AllPatchSetApprovalsProto.parser()));