Add Qt6 build support
Changes
- Use
BUILD_WITH_QT6inCMakeLists.txtto find Qt6 libraries - Add Linux, FreeBSD and Windows builds to
.gitlab-ci.yml - Fix
setTime_t/toTime_tobsolete methods (replaced withsetSecsSinceEpoch/toSecsSinceEpoch) - Use
QRegularExpressionfor Qt6 - Fix error with
git_commit_createintroduced inv1.8.0. This change will be reverted inv1.8.2(https://github.com/libgit2/libgit2/commit/49d3fadfca4ce8e7a643525eb301a2d45956641e)