Calendar: remove past events.

wiki/src/contribute/calendar.mdwn

@@ -4,14 +4,6 @@ All times are referenced to Berlin and Paris time.
 
 ## 2019Q1
 
-* 2019-06-17 and 2019-06-18: Buster (remote) sprint
-
-* 2019-06-19, 16:00 Fundraising meeting
-
-* 2019-06-25 to 2019-06-27: Translation platform sprint
-
-* 2019-07-03, 16:00: [[Foundations Team|contribute/working_together/roles/foundations_team]] meeting
-
 * 2019-07-09: **Release 3.15** (Firefox 60.8, Tor Browser 8.5; bugfix release — kibi is the RM)
 
 * 2019-07-17, 16:00 Fundraising meeting