dvc: temporarily hide `dvc tag`
dvc: temporarily hide `dvc tag`

This feature is not yet ready for public use.

Signed-off-by: Ruslan Kuprieiev <e9bfb2c543dd33934bcff71879b108246996b567@iterative.ai>

efiop/dvc,dataversioncontrol/dvc,efiop/dvc,dmpetrov/dataversioncontrol,dmpetrov/dataversioncontrol,dataversioncontrol/dvc