[publications] update author list for E-ACSL user manual

_fc-publications/e-acsl/user-manual.md

 ---
 plugin: "e-acsl"
-authors: "Julien Signoles and Kostyantyn Vorobyov"
+authors: "Julien Signoles, Basile Desloges and Kostyantyn Vorobyov"
 title: "E-ACSL User Manual"
 link: "http://frama-c.com/download/e-acsl/e-acsl-manual.pdf"
 category: manuals