fix: CRAN issues

[Fersoil]

Checklist

• I added a very descriptive title to this issue.
• I used the GitHub search to find a similar question and didn't find it.
• I am sure that this is a bug in SerolyzeR package rather than my code.
• The bug is not resolved by updating to the latest stable version of SerolyzeR package.
• I included a link to the documentation page I am referring to (if applicable).

Reproduction steps

If there are references describing the methods in your package, please
add these in the description field of your DESCRIPTION file in the form
authors (year) doi:...
authors (year, ISBN:...)
or if those are not available: https:...
with no space after 'doi:', 'https:' and angle brackets for
auto-linking. (If you want to add a title as well please put it in
quotes: "Title")
For more details:
https://contributor.r-project.org/cran-cookbook/description_issues.html#references

Please write TRUE and FALSE instead of T and F. Please don't use "T" or
"F" as vector names.
e.g.: in tests/testthat/test-process-dir.R
For more details:
https://contributor.r-project.org/cran-cookbook/code_issues.html#tf-instead-of-truefalse

Please make sure that you do not change the user's options, par or
working directory. If you really have to do so within functions, please
ensure with an immediate call of on.exit() that the settings are reset
when the function is exited.
e.g.:
...
old <- options() # code line i
on.exit(options(old)) # code line i+1
...
options(scipen = 30) # somewhere after
...
e.g.: -> R/plots-standard_curve.R
If you're not familiar with the function, please check ?on.exit. This
function makes it possible to restore options before exiting a function
even if the function breaks. Therefore it needs to be called immediately
after the option change within a function.
For more details:
https://contributor.r-project.org/cran-cookbook/code_issues.html#change-of-options-graphical-parameters-and-working-directory

Please fix and resubmit.

Error Message and Stack Trace (if applicable)

No response

OS

No response