v0.13.9

Catlab v0.13.9

Diff since v0.13.8

Closed issues:

• Migrate graph interop from LightGraphs to Graphs (#613)
• using Catlab fails (#618)

Merged pull requests:

• Slice categories (#591) (@kris-brown)
• Migrate from LightGraphs.jl to Graphs.jl (#614) (@epatters)
• GAT for M-categories (#616) (@epatters)
• Support expressions of form f(x) == g(y) in diagram DSL (#617) (@epatters)
• Representables and the Yoneda embedding (#621) (@epatters)
• Fix allocation of unique indices for morphisms in C-sets (#622) (@epatters)
• Improved Graphviz drawing of graphs and categories (#625) (@epatters)
• Bump Documenter to v0.27 (#626) (@epatters)