devtools is moving away from remotes

Hi, I will release devtools soon and I notice this causes an issue for ggtaxplot. You can see the result here:

https://github.com/r-lib/devtools/blob/6a65ffbdf16623c36c0bbeda46867974a8526c49/revdep/problems.md?plain=1#L1-L32

devtools has deprecated its install_*() functions, in favor of sending folks to the pak package. As a consequence, remotes has moved from Imports to Suggests.