Update codimd template

[sstevens2]

What is the problem?

Think there were a couple places earlier I saw the template needed to be updated but didn't write them down unfortunately at the time. @tobyhodges please note if you remember where needs updating

I do remember that there are:

1. no key points for the adding lesson content episode
2. the first point of the Exercise: More Practice in the adding lesson content episode is something they now do as part of the lesson and is removed from the lesson version of this exercise
3. Update exercise Completing episode metadata in the writing content episode still has a reference to the workbench in it, which was removed from the lesson since the workbench comes later

Location of problem (optional)

No response