[Integrated] RFR: git-sync: use refspec instead of --prune-tags

[Erik Helin]

Changeset: b2b8de24
Author:    Erik Helin <ehelin at openjdk.org>
Date:      2020-03-23 08:06:30 +0000
URL:       https://git.openjdk.java.net/skara/commit/b2b8de24

git-sync: use refspec instead of --prune-tags

Reviewed-by: rwestberg

! vcs/src/main/java/org/openjdk/skara/vcs/git/GitRepository.java