Package dependency for 'proj4' is missing

[trinetra75]

The package is actually failing on BioConductor due to a missing dependency about 'proj4'.

Please add the package in the DESCRIPTION file as one of the Imports

Here is the message from the BioConductor failing build:

Quitting from lines 407-426 [ex9] (PCAtools.Rmd)
Error: processing vignette 'PCAtools.Rmd' failed with diagnostics:
there is no package called 'proj4'