update versions.yml
Merge branch '2.9.1' into 2.9.0
Update sitemap
Create 2.9.1.md
Update for 2.9.1
Update versions.yml for 2.9.1
Add Marie Curie logo to affiliations
Initial commit 2nd part workshop.

Signed-off-by: lvanderlinden <l.vanderlinden@cogsci.nl>
Changes 2nd part workshop

Signed-off-by: lvanderlinden <l.vanderlinden@cogsci.nl>