Changelog for haggle-0.2

0.2 (2022-05-08)

Exported the vertexId function to project an Int from a Vertex, which is useful for conversions to other formats (e.g., graphviz) (@benjaminselfridge)
Fixed a bug in the BiDigraph that prevented parallel edges from being added to the graph (@benjaminselfridge)
Added Unbox instances for Vertex and Edge (@bielr)
Added a Bifunctor instance for the PatriciaTree (@kquick)