build: re-add 'Rmalschains' in the 'Suggests' list

- remove the explanations from the vignette '2.1_param_optim' about the installation of the package from the CRAN archives
- add the package in the 'Suggests' list of the DESCRIPTION file
Refs: #175

DESCRIPTION

@@ -28,7 +28,7 @@ Imports:
   utils
 Suggests:
   knitr, markdown, rmarkdown,
-  caRamel, coda, DEoptim, FME, ggmcmc,
+  caRamel, coda, DEoptim, FME, ggmcmc, Rmalschains,
   GGally, ggplot2,
   testthat
 Description: Hydrological modelling tools developed at INRAE-Antony (HYCAR Research Unit, France). The package includes several conceptual rainfall-runoff models (GR4H, GR5H, GR4J, GR5J, GR6J, GR2M, GR1A) that can be applied either on a lumped or semi-distributed way. A snow accumulation and melt model (CemaNeige) and the associated functions for the calibration and evaluation of models are also included. Use help(airGR) for package description and references.

vignettes/V02.1_param_optim.Rmd

@@ -14,7 +14,7 @@ vignette: >
 library(airGR)
 library(DEoptim)
 # library(hydroPSO) # Needs R version >= 3.6 or latticeExtra <= 0.6-28 on R 3.5. Archived on 2023-10-16 as requires archived packages 'hydroTSM' and 'hydroGOF'. 
-# library(Rmalschains) # removed from CRAN since 2023-04-03
+library(Rmalschains)
 library(caRamel)
 library(ggplot2)
 library(GGally)
@@ -179,12 +179,6 @@ optPSO <- hydroPSO::hydroPSO(fn = OptimGR4J,
 
 ## MA-LS-Chains
 
-```{r, warning=FALSE, results='hide', message=FALSE, eval=FALSE}
-# to install the package temporary removde from CRAN
-# Rtools needed (windows : https://cran.r-project.org/bin/windows/Rtools/)
-install.packages("https://cran.r-project.org/src/contrib/Archive/Rmalschains/Rmalschains_0.2-8.tar.gz", 
-                 repos = NULL, type = "source", dependencies = TRUE)
-```
 ```{r, warning=FALSE, results='hide', eval=FALSE}
 optMALS <- Rmalschains::malschains(fn = OptimGR4J,
                                    lower = lowerGR4J, upper = upperGR4J,