If you are equipping a melee weapon with the operative special quality, you can use dextery instead of strength to perform the melee attack. Nevertheless it seems to only use the Strength modificator and I can not find any options to toggle to use dexterity.
This was produced using 6.07.03 with the Starfinder_Install_v2017_09_15.rev.1.06.zip file installed. (as noted in the blog http://pcgen.org/2017/09/17/starfinder-v1-6-released/)
Tested with: "Knife, survival" and "Baton, tactical" and a character with 8 STR and 18 DEX (character attached)