Update skeletong to show available bibliostyle

fix #545

DESCRIPTION

@@ -1,7 +1,7 @@
 Type: Package
 Package: rticles
 Title: Article Formats for R Markdown
-Version: 0.25.1
+Version: 0.25.2
 Authors@R: c(
     person("JJ", "Allaire", , "jj@posit.co", role = "aut"),
     person("Yihui", "Xie", , "xie@yihui.name", role = "aut",

NEWS.md

@@ -1,5 +1,7 @@
 # rticles (development version)
 
+- `elsevier_article()` Rmd skeleton is now updated to show different available bibliostyle file (i.e `*.bst` for _natbib_) with `elsearticle` document class. `biblio-style: elsarticle-harv` is set by default to correctly work with the `authoryear` classoption already set (thanks, @pepijn-devries, #545).
+
 # rticles 0.25
 
 ## BREAKING CHANGES

inst/rmarkdown/templates/elsevier/skeleton/skeleton.Rmd

@@ -45,10 +45,11 @@ keywords:
   - keyword2
 journal: "An awesome journal"
 date: "`r Sys.Date()`"
-classoption: preprint, 3p, authoryear
-bibliography: mybibfile.bib
 linenumbers: false
 numbersections: true
+bibliography: mybibfile.bib
+biblio-style: elsarticle-harv # author year style for natbib - use 'elsarticle-num' or 'elsarticle-num-names' for numbered scheme
+classoption: preprint, 3p, authoryear # remove authoryear is not using `elsarticle-harv`
 # Use a CSL with `citation_package = "default"`
 # csl: https://www.zotero.org/styles/elsevier-harvard
 output: 
@@ -68,7 +69,8 @@ For detailed instructions regarding the elsevier article class, see   <https://w
 
 Here are two sample references: @Feynman1963118 [@Dirac1953888].
 
-By default, natbib will be used with the `authoryear` style, set in `classoption` variable in YAML. 
+By default, natbib will be used with the `authoryear` style, set in `classoption` variable in YAML and with `elsearticle-harv.bst` which is among provided style by `elsarticle` documentclass. Other available style are `elsarticle-num.bst` and `elsarticle-num-names.bst` — the first one can be used for the numbered scheme, second one for numbered with new options of natbib.sty. 
+
 You can sets extra options with `natbiboptions` variable in YAML header. Example 
 ```yaml
 natbiboptions: longnamesfirst,angle,semicolon