Add multishot powerup

[LordDeatHunter]

The magic "spread angle" numbers could probably use some tweaking. Here's how it currently looks ingame (triple shot, screenshot taken mid gameplay):

Also, not completely satisfied with how the "distance" forms, maybe we can have some randomization or smoothing out in the future. (this is a lot of projectiles, mostly as an example of how they stack over time)

I also made it a guaranteed drop from the Repeater boss. Had to make a new loot-table for it. By default, it's a 1% drop from other enemies.

[varoonp123]

CI is failing for an unenlightening reason. We will need to merge #111 first.

[cdsupina]

@varoonp123 and I tested this and found that when the Juggernaut character has multi-shot, the projectiles collide with each other due to their hitbox. Perhaps adjust the position or angle of the projectiles.

[cdsupina]

Pull main to fix CI.

[LordDeatHunter]

(copied from discord)

Update on this: I can't find a clean all-encompassing solution.

1. Spreading the bullets a bit initially kinda works, but it gets janky with more projectiles:
   • if the "spread" amount isn't increased over time, the bullets start colliding
   • otherwise, they keep spreading out, making "horizontal lines" across the map after a couple of powerups
2. A similar solution would be to instead disable the collider on the bullets when they're spawned, and enable it some 0.5s after. Not sure how this will affect gameplay. It might be the most "middle ground" solution.
3. Disabling "explosions" (despawning) on bullet collision makes it weird (they ricochet a lot & makes their movement very unpredictable)
4. Disabling collision between same-type bullets - should in theory work, but I'm not sure on the affect on gameplay.
5. The projectile powerups only affecting the main character. Bullet-characters either not being able to pick up the powerup, not getting anything, or getting a different power.

I'll leave the PR open for now, in case there are some other ideas 🙂

[LordDeatHunter]

Updated look of the projectile arc:

[LordDeatHunter]

Juggernaut is now also sexy 💗 However, it's hard to fight the Repeater boss, since all the projectiles launch the boss upwards. Also noticeable with just 2 projectiles.

[cdsupina]

We can try decreasing the mass of the projectiles, or increasing the speed (so it can recover faster) or mass of the boss. Either way though, I think for now it's fine and this is just a matter of balancing some values.