Events: Update PyWeek 37 from Ongoing to Recent event

It's not completely over yet as the winners are yet to be announced, but
the coding phase, as shown in the date "March 17-24th" has passed so it
no longer makes sense to list it as ongoing.

pydis_site/templates/events/current_event.html

@@ -2,7 +2,7 @@
 
 {# Current/next event to promote #}
 <div class="box has-background-warning-light" style="padding: 2rem; padding-top: .75rem; margin-top: 2rem;">
-    <small class="has-text-grey">Ongoing event</small>
+    <small class="has-text-grey">Recent event</small>
     <div class="columns is-3 mt-1" style="--columnGap: 0.75rem;">
         <div class="column">
             <h2 class="title is-4"><a href="https://pyweek.org/37/">PyWeek 37</a></h2>