Weekly release of rdiff-backup

Hi,

I just wanted to announce that we have now weekly releases.

They are available always under the same tag at 
https://github.com/rdiff-backup/rdiff-backup/releases/tag/weekly

And they are (re-)generated each night from Sunday to Monday at 22:22 
UTC.

They are not meant for production use. You can use them for testing and 
reporting bugs (that would be nice) and/or verify that recent evolutions 
fulfill your expectations.

KR, Eric