does the bomb gear token does additional damage with void gate?

Radiance rules aren't published yet. This uses the printed card and current rules only, and it isn't a ruling on the new mechanics.

Yes — the Bomb token's death trigger deals 3 instead of 2 if the Bomb is at Void Gate. Void Gate says "Spells and abilities deal 1 Bonus Damage to units here," and the Bomb's "When it dies, deal 2 to an enemy there" is a triggered ability that deals the damage itself (unlike Challenge, where units deal the damage and so get nothing — FAQ #3440). Since "there" means the Bomb's own location (Deploy puts it at a battlefield), the enemy being hit is a unit at Void Gate, so the bonus applies per Rule 715.1.

Each instance of damage is increased once, so the single "deal 2" becomes 3, not two separate hits. If you also control Ziggs, Short-Fused ("Abilities of friendly gear deal 1 Bonus Damage"), both instances are summed per Rule 714 and the trigger deals 4.

This is my interpretation based on Rule 715 and Void Gate's printed text. No official FAQ exists for this specific interaction.