Expose force=TRUE to git_branch_create()

[MichaelChirico]

Encountered this error:

gert::git_branch_create(paste(sample(letters), collapse = ""), ref = tag_hash)
# Warning: Your local changes to the following file would be overwritten by checkout: .dev/compare_branches.R
# Use force = TRUE to checkout anyway.
# Error in libgit2::git_checkout_tree : 1 conflict prevents checkout

At a glance here is the triggering line:

gert/src/branch.c

Line 65 in abc3d4d

bail_if(git_checkout_tree(repo, obj, &opts), "git_checkout_tree");

I am running gert from a copy of a repo in tempdir(), so I don't care much about overwrites; this error message suggests force=TRUE is possible, but not yet exposed to the R API. Is it possible to do so?