World Editor > Advanced > Gameplay Constants... > Tick the Use Custom Gameplay Constants > Hero Attributes - Attack Speed Bonus per Agility Point: Change this
Current values for each new map should be 0.02, 0.02 is evaluated in percentage, so 0.02 means 0.02% per Agility Point.
You want it to be 1% per 5 AGI point right ?
You should change the 0.02 to 0.2
So now it gives you 0.2% per AGI Point, resulting in 1% per 5 AGI Point.