editor puts local config setting into global config

Steps to reproduce

$ beat config show
{
    "user": "user"
}
$ cat ~/.beatrc
{
    "user": "user"
}
$ beat config set --local user tst
$ beat config show
{
    "user": "tst"
}
$ cat ~/.beatrc
{
    "user": "user"
}
$ beat editor start
# do nothing, exit editor
$ cat ~/.beatrc
{
    "user": "tst"
}