Addressing warning messages when using test_sharp_null()

[MikkelVembye]

Hi Jonathan,

Thank you sincerely for a wonderful paper and software package. My team and I are very much looking forward to using your work.

While testing the package, we encountered the following warning messages:

Warning messages: 1: In library(package, lib.loc = lib.loc, character.only = TRUE, logical.return = TRUE, : there is no package called ‘lpinfer’ 2:cross_df()was deprecated in purrr 1.0.0. ℹ Please usetidyr::expand_grid()instead. ℹ See <[https://github.com/tidyverse/purrr/issues/768](vscode-file://vscode-app/c:/Users/B199526/AppData/Local/Programs/Positron/resources/app/out/vs/code/electron-browser/workbench/workbench.html#)>. ℹ The deprecated feature was likely used in the TestMechs package. Please report the issue to the authors. This warning is displayed once every 8 hours. Calllifecycle::last_lifecycle_warnings()to see where this warning was generated. 3:cross()was deprecated in purrr 1.0.0. ℹ Please usetidyr::expand_grid()instead. ℹ See <[https://github.com/tidyverse/purrr/issues/768](vscode-file://vscode-app/c:/Users/B199526/AppData/Local/Programs/Positron/resources/app/out/vs/code/electron-browser/workbench/workbench.html#)>. ℹ The deprecated feature was likely used in the purrr package. Please report the issue at <[https://github.com/tidyverse/purrr/issues](vscode-file://vscode-app/c:/Users/B199526/AppData/Local/Programs/Positron/resources/app/out/vs/code/electron-browser/workbench/workbench.html#)>.
These warnings caused some confusion among my colleagues, particularly those who primarily use Stata. To accommodate this, I have added lpinfer to Remotes in the DESCRIPTION file. In addition, I have updated purrr::cross_df() to tidyr::expand_grid() and added tidyr to Imports.

All the best to you, and once again, thank you.

Best wishes,
Mikkel