Add JuliaCon presentation

CITATION.bib

@@ -1,16 +1,9 @@
-@software{legat2021polyhedra,
-  author       = {Benoît Legat and
-                  Robin Deits and
-                  Gustavo Goretkin and
-                  Twan Koolen and
-                  Joey Huchette and
-                  Daisuke Oyama and
-                  Marcelo Forets},
-  title        = {JuliaPolyhedra/Polyhedra.jl: v0.6.16},
-  month        = jun,
-  year         = 2021,
-  publisher    = {Zenodo},
-  version      = {v0.6.16},
-  doi          = {10.5281/zenodo.4993670},
-  url          = {https://doi.org/10.5281/zenodo.4993670}
+@Conference{legat2023polyhedral,
+  author    = {Legat, Beno{\^\i}t},
+  title     = {Polyhedral Computation},
+  month     = jul,
+  year      = 2023,
+  booktitle = {JuliaCon},
+  year      = {2023},
+  url       = {https://pretalx.com/juliacon2023/talk/JP3SPX/},
 }

README.md

@@ -23,7 +23,8 @@ It defines the abstract type `Polyhedron` and splits the operations on this type
 
 ## Citing
 
-See [CITATION.bib](https://github.com/JuliaPolyhedra/Polyhedra.jl/blob/master/CITATION.bib).
+Please cite the [JuliaCon 2023 presentation](https://pretalx.com/juliacon2023/talk/JP3SPX/) [[Slides](https://drive.google.com/file/d/1iSalXEqRO3AjHLm-3TqYLjby267n6uo5/view)].
+See [CITATION.bib](https://github.com/JuliaPolyhedra/Polyhedra.jl/blob/master/CITATION.bib) for the BibTeX.
 
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