My suggestion is to buy the game first and see how you do.
You more than meet the minimum requirements:
https://us.battle.net/support/en/article/109713
If you find performance lacking, do some tests:
a) Run YOUR games, but lower your resolution and eye candy.
If your FPS increases, it indicates that your cpu is strong enough to drive a better graphics configuration.
If your FPS stays the same, you are likely more cpu limited.
b) Limit your cpu, either by reducing the OC, or, in windows power management, limit the maximum cpu% to something like 70%.
Go to control panel/power options/change plan settings/change advanced power settings/processor power management/maximum processor state/
This will simulate what a lack of cpu power will do.
Conversely what a 30% improvement in core speed might do.
If you need better graphics, make it a big jump or you may be disappointed if you do not see big results.
Something like a GTX1080.
If you need more cpu, that is a more difficult question.
Your I3-6100 has 4 threads and runs at a 3.7 clock.
A $350 I7-7700K has 8 threads and will run at 4.2 with a higher turbo at stock. No overclock required.
You may need a bios update for your motherboard to run a kaby lake processor.
You will also need more than a stock cooler. The scythe kotetsu @$35 is my favorite bargain cooler.
If your budget is more modest, I see two options.
A $210 I5-7600K will run at 3.8, a miniscule single thread update, but give you 4 full threads.
It is not clear to me how many threads can effectively be used by the game.
Most games can only use 2-3.
A more interesting upgrade would be the $150 I3-7350K.
It has been panned as not great, but the price has come down and you get the same 4.2 clock as the 7700K but only 4 threads.
I suggested you buy the game first so you can do some testing.
You can now test how important many threads are to your current games.
You can do this in the windows msconfig boot advanced options option.
You will need to reboot for the change to take effect. Set the number of threads to one less than you have.
This will tell you how sensitive your games are to the benefits of many threads.
If you see little difference, your game does not need all the threads you have.