version 1.2.2 (last update 2021-08-13)
+ Add rmarkdown to the suggests field

version 1.2.1 (last update 2021-08-05)
+ Add warnings for small sample size.

version 1.1.5 (last update 2021-03-09)
+ Bugs fix: fix the bug of inflated p-values and inconsistent output formats.

version 1.1.4 (last update 2021-02-28)
+ Bug fix: fix the bug when metadata contains only a single variable and some
samples were removed with the minimum library size cutoff.

version 1.1.3 (last update 2021-02-19)
+ Add a warning message for the case of the small number of taxa.

version 1.1.2 (last update 2020-12-08)
+ Bug fix: fix the bug that the sampling fraction estimate will return a
single number instead of a vector.

version 1.1.1 (last update 2020-11-20)
+ Integrating with functions from the microbiome package.

version 1.0.0: (2020-10-31)
+ Release!
