fix: [Articles_essentiels] missing comma - make Bib file parseable

Articles_essentiels.bib

@@ -82,7 +82,7 @@
   pages={87--108},
   year={2018},
   keyword = {datasphère, cyberespace, révolution numérique, géopolitique, diplomatie},
-  url = {https://journals.openedition.org/netcom/3419}
+  url = {https://journals.openedition.org/netcom/3419},
   publisher={Netcom Association}
 }