Update bindings to the latest version 0.3.8
Improve clarity by adding spaces
Update org-trello logo
Add a credit section to thank contributions
Enforce the updates regarding the bindings
Update the migration guide regarding the 0.3.8
Open PR target
Merge pull request #4 from ardumont/update-to-version-0.3.8

Update documentation to match org-trello 0.3.8