Update CITATION

Author: mingdeyu

inst/CITATION

@@ -50,12 +50,12 @@ bibentry(bibtype = "Manual",
   title        = "dgpsi: An R package powered by Python for modelling linked deep Gaussian processes",
   author       = c(as.person("Deyu Ming"),
                    as.person("Daniel Williamson")),
-  note         = "R package version 2.4.0",
+  note         = "R package version 2.6.0",
   url          = "https://CRAN.R-project.org/package=dgpsi",
-  year         = "2024",
+  year         = "2025",
 
   textVersion  =
-  paste("Ming, D. and Williamson, D. (2024)",
+  paste("Ming, D. and Williamson, D. (2025)",
         "dgpsi: An R package powered by Python for modelling linked deep Gaussian processes,",
-        "R package version 2.4.0. https://CRAN.R-project.org/package=dgpsi.")
+        "R package version 2.6.0. https://CRAN.R-project.org/package=dgpsi.")
 )