update seminar.md: add a link to Andre's talk

It seems even "Developer" cannot push his commit to protected-branches including the master branch. Thus, I need to open this Merge Request. Please kindly merge it.

I've changed the settings and you should now be allowed to both push and merge. (I'll let you merge this request so we can see if it works now :) )

merged

mentioned in commit ae82d3fc

It works. Thanks!