Update before I tag

Note: reproducible builds don't quite work yet. Once we can update to
bnd 5.4.0 the reproducible builds should be possible.
I'm mainly doing this to get into the habit of doing it as part of the
release.
diff --git a/build.properties.default b/build.properties.default
index bce6fdd..0f78322 100644
--- a/build.properties.default
+++ b/build.properties.default
@@ -31,8 +31,8 @@
 
 # ----- Reproducible builds -----
 # Uncomment and set to current time for reproducible builds
-#2021-03-18T06:00:00Z
-#ant.tstamp.now=1616047200
+#2021-05-08T15:00:00Z
+#ant.tstamp.now=1620482400
 
 # ----- Source control flags -----
 git.branch=master