For testers : access every day of nightly build of Kunena

Since couple of days, we have set up into github actions a workflow which automatically create a new build every day at 23:00 UTC and upload in FTP of kunena.org. It create only a new build on the K7.0 branch (which is the default branch) not others branches. The new build is directly available in https://www.kunena.org/download under Nightly Builds. For people which wnats make pull requests, the K6.4 branch is only for security fix, the K7.0 branch is for bug and security fixes and the branch K7.1 is for new features. This will change after teh stable release of K7.1 because the K7.0 won't get anything.