tg beta endpoints update adds --ab-percent to change A/B variant traffic

tg beta endpoints update now accepts --ab-percent to change a variant's traffic percentage in an existing A/B experiment. The flag takes percentage from or returns it to the control only. Other variants stay unchanged. The control must remain at least 1%, and --percent on tg beta endpoints ab is limited to 1–99.

See Ramp the variant and the endpoints CLI reference.