A .mailmap entry for @huitseeker

Without this, the release notes generator considers him
as two distinct beings:

    List(F, r, a, n, c, ̧, o, i, s,  , G, a, r, i, l, l, o, t)
    List(F, r, a, n, ç, o, i, s,  , G, a, r, i, l, l, o, t)
Merge pull request #2999 from retronym/topic/mailmap-francois

A .mailmap entry for @huitseeker