vegandevs/vegan: vegan 2.6-2 in CRAN

New CRAN release was based on the current master branch. The old cran-2.5 will no longer be updated. For details of changes, see the NEWS in the package. Use command news(package="vegan") in R session to read the news. Here a brief summary: Compiled code was fixed for upcoming R 4.2.0 release, and you must upgrade vegan with new R. Several functions can now return their results in tidy format allowing easier use of ggplot2 graphics. adonis2 is the new major function for analysis of dissimilarites. The old adonis is still available, but it will be deprecated in the next minor release. Aitchison and robust Aitchison distances and standardization were added. Unbiased Simpson diversity was added, and diversity gained a groups argument for pooled diversities. Following github issues were addressed: #369, #393, #401, #427, #447, #463, #497, #501, #507