[12.0][mail_show_follower] Update version
[12.0][mail_show_follower] Update version

As commented in https://github.com/OCA/social/pull/788 the PR should be merged manually but we should update the version of the module as a minor update

cc @ValentinVinagre @eLBati @MiquelRForgeFlow @HaraldPanten

OCA/social,OCA/social,OCA/social