coq-graph-theory version 0.8

[chdoc]

This should be compatible with coq-8.13 as well, but as of now there is no way to satisfy the dependencies, so I'm limiting this to <8.13~

[chdoc]

@gares am I right to assume that this build failure is due to elpi1.11.4-1 being incompatible with dune-2.7.x but not setting an upper bound? : https://github.com/ocaml/opam-repository/blob/master/packages/elpi/elpi.1.11.4-1/opam#L31

CC: @damien-pous

[palmskog]

@chdoc I believe is related to #1286. So maybe we should merge this PR in spite of the failure on any build?

[gares]

Yes, I believe it's the usual bug. I say green light.