CheckerConfigSubject: Fix raw type warning

Signed-off-by: Edwin Kempin <ekempin@google.com>
Change-Id: I1543e5b29eeb41f001f469c21c916390b28fbf4a
diff --git a/java/com/google/gerrit/plugins/checks/testing/CheckerConfigSubject.java b/java/com/google/gerrit/plugins/checks/testing/CheckerConfigSubject.java
index e74f050..8e5bb2c 100644
--- a/java/com/google/gerrit/plugins/checks/testing/CheckerConfigSubject.java
+++ b/java/com/google/gerrit/plugins/checks/testing/CheckerConfigSubject.java
@@ -32,6 +32,7 @@
 import com.google.gerrit.plugins.checks.db.CheckerConfig;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.truth.OptionalSubject;
+import java.sql.Timestamp;
 import java.util.Optional;
 import org.eclipse.jgit.lib.Config;
 
@@ -87,7 +88,7 @@
     check("query()").about(optionals()).that(checker().getQuery()).isEmpty();
   }
 
-  public ComparableSubject hasCreatedThat() {
+  public ComparableSubject<Timestamp> hasCreatedThat() {
     return check("created()").that(checker().getCreated());
   }