state: use json.dumps() instead of dump()
state: use json.dumps() instead of dump()

This actually 10 times faster, because everything is stored in the
memory.

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

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