Merge branch 'cl/rerere-train-with-no-sign'

"rerere-train" script (in contrib/) used to honor commit.gpgSign while recreating the throw-away merges. source: <PH7PR14MB5594A27B9295E95ACA4D6A69CE8F9@PH7PR14MB5594.namprd14.prod.outlook.com> * cl/rerere-train-with-no-sign: contrib/rerere-train: avoid useless gpg sign in training