error: unknown option `detach' about falcon-plus HOT 2 CLOSED

➜  ~ git --version
git version 2.12.0

➜  ~ git checkout --help|grep detach
       git checkout [-q] [-f] [-m] --detach [<branch>]
       git checkout [-q] [-f] [-m] [--detach] <commit>
       git checkout --detach [<branch>], git checkout [--detach] <commit>
           Prepare to work on top of <commit>, by detaching HEAD at it (see "DETACHED HEAD" section), and updating the index and the files in the working tree. Local modifications to
           When the <commit> argument is a branch name, the --detach option can be used to detach HEAD at the tip of the branch (git checkout <branch> would check out that branch
           without detaching HEAD).
           Omitting <branch> detaches HEAD at the tip of the current branch.
       --detach
           refers to a valid commit, your HEAD becomes "detached" and you are no longer on any branch (see below for details).
           As a special case, the "@{-N}" syntax for the N-th last branch/commit checks out branches (instead of detaching). You may also specify - which is synonymous with "@{-1}".
       Notice that regardless of which checkout command we use, HEAD now refers directly to commit b. This is known as being in detached HEAD state. It means simply that HEAD refers
       1. creates a new branch foo, which refers to commit f, and then updates HEAD to refer to branch foo. In other words, we’ll no longer be in detached HEAD state after this
       2. similarly creates a new branch foo, which refers to commit f, but leaves HEAD detached.
       3. creates a new tag foo, which refers to commit f, leaving HEAD detached.