loop: change current_datetime to current_date

So that we don't always invalidate the k/v cache.

Co-Authored-By: sketch <hello@sketch.dev>
Change-ID: s330e5fc0212d37d4k
diff --git a/loop/agent.go b/loop/agent.go
index 4b8f62c..872f77f 100644
--- a/loop/agent.go
+++ b/loop/agent.go
@@ -2434,7 +2434,7 @@
 		Codebase:          a.codebase,
 		UseSketchWIP:      a.config.InDocker,
 		InstallationNudge: a.config.InDocker,
-		Now:               now.Format(time.DateTime),
+		Now:               now.Format(time.DateOnly),
 	}
 	if now.Month() == time.September && now.Day() == 19 {
 		data.SpecialInstruction = "Today is international talk like a pirate day. Occasionally drop a 🏴‍☠️ into the conversation (not code!), but subtly."