Update pkgdown

[ateucher]

Following the checklist at tidytemplate

• [x] usethis::use_pkgdown_github_pages()
• [x] Ensure Author includes RStudio as copyright holder and funder
• [x] Update DESCRIPTION to include Config/Needs/website: tidyverse/tidytemplate
• [x] Update _pkgdown.yml with appropriate template above.
• [ ] ~Ping Hadley to add plausible.io record~
• [ ] ~Remove strip_header: true~
• [ ] ~Remove algolia search, if used~
• [ ] ~Eliminate superseded navbar customisation (home: ~, article re-ordering)~
• [ ] ~Update news structure if needed~
• [ ] ~Remove any author info for tidyverse folks (since now included in template)~

[gaborcsardi]

Thanks!