Add training program publication milestones

_roadmap/software/2021-02-26-tasks.md

+---
+date: 2021-02-26
+title: Tasks in February 2021
+service: software
+---
+
+## Publish training program for the first half of 2021 
+The education and training work package publishes the offered training events for the first half of 2021 on https://software.hifis.net/events.

_roadmap/software/2021-06-30-tasks.md

+---
+date: 2021-06-30
+title: Tasks in June 2021
+service: software
+---
+
+## Publish training program for the second half of 2021 
+The education and training work package publishes the offered training events for the second half of 2021 on https://software.hifis.net/events.