Change name of PDF of the sponsorship brochure

[Rantignac]

Description

Currently the name of the brochure is static. It will be replaced by something dynamic
eg : sponsorship-{event-name}-v{version}-{date-atom}.pdf

[kevinjhappy]

As event-name is asked into the brochure name, as long as the PR #146 is not merged and the issue #103 is not close, this task cannot be made yet