added latest DOI to citation

inst/CITATION

@@ -11,7 +11,7 @@ bibentry(bibtype = "Manual",
   title = "elevatr: Access Elevation Data from Various APIs",
   year = "2023",
   note = "R package version 0.99.0",
-  doi = "10.5281/zenodo.5809645",
+  doi = "10.5281/zenodo.8335450",
   url = "https://github.com/jhollist/elevatr/",
   textVersion = "Hollister, J.W. (2023). elevatr: Access Elevation Data from Various APIs. R package version 0.99.0. https://CRAN.R-project.org/package=elevatr/"
 )