v0.2.0

Changes Since 0.1.1

• Bumped MSRV to 1.34.1.
• Reduced size of Index by limiting Arena to 2^32 elements and 2^32 generations per slot.
  • These limits should not be hit in practice, but will consistently trigger panics.
• Changed generation counter to wrap instead of panic on overflow.
  • Collisions where an index using the same slot and a colliding generation on [1, 2^32] should be incredibly unlikely.