Official release of libspf2 1.2.11

[atoomic]

I noticed that several distro are packaging libspf2
and need to use a tarball from the github repo (and specify the git id they used)
as it seems that the last official version listed from https://www.libspf2.org is 1.2.10

view: https://www.libspf2.org/download.html

Example with Fedora:
https://src.fedoraproject.org/rpms/libspf2

extract from the spec file https://src.fedoraproject.org/rpms/libspf2/blob/rawhide/f/libspf2.spec

%global git 4915c308

Note: using some git tags with the release version would also be useful.

Refs: #33

[toddr]

TBH, at this point, enough people have been using 1.2.11 unofficially, that it might be good to bump the release to 1.2.12 :)

[eriklax]

I think it would be very benficial for the community to collect the necessary patches from pull requests and from debian (if there are some missing) an have them applied before 1.2.12, using 1.2.11 in production without patches is currently not possible.

I would really like to get rid of my patch branch, and I can definitely help out finding and submitting patches if there is a merge window.