add project.build.outputTimestamp for reproducible builds

Signed-off-by: Raymond Augé <rotty3000@apache.org>
diff --git a/pom.xml b/pom.xml
index e5b7260..b36acc9 100644
--- a/pom.xml
+++ b/pom.xml
@@ -36,6 +36,7 @@
 		<java.build.version>1.8</java.build.version>
 		<maven.compiler.source>${java.build.version}</maven.compiler.source>
 		<maven.compiler.target>${java.build.version}</maven.compiler.target>
+		<project.build.outputTimestamp>10</project.build.outputTimestamp>
 
 		<bnd.version>6.1.0</bnd.version>
 	</properties>