Change header levels in custom-diagnostic vignette

[maelle]

I noticed this vignette has no TOC in the pkgdown website :-)

[MichaelChirico]

for the GHA failure, is the v1->v2 switch for r-lib/actions easy? feel free to point to some documentation, or just edit the workflow, or demur if you don't know offhand :)

[maelle]

I think it's easy if you use usethis setup functions and overwrite/delete former files. It also depends on whether your current workflows were customized in which case the customizations have to be ported.

I ran

• usethis::use_github_action("pkgdown");
• usethis::use_github_action("test-coverage");
• usethis::use_github_action_check_standard().

I re-added the timeout and the comment in two of the files. Please look whether I forgot other important customizations.

[MichaelChirico]

Thanks! I'm happy if checks are green :)