Release googlesheets4 1.0.0

[jennybc]

Prepare for release:

• [x] Check current CRAN check results
• [x] Polish NEWS
• [x] devtools::build_readme()
• [x] urlchecker::url_check() had to switch Discovery Document URLs to verbatim text because HEAD 404s for them, even though they are browsable
• [x] devtools::check(remote = TRUE, manual = TRUE)
• [x] devtools::check_win_devel()
• [x] rhub::check_for_cran()
• [x] revdepcheck::revdep_check(num_workers = 4)
• [x] Update cran-comments.md
• [x] Review pkgdown reference index for, e.g., missing topics
• [x] Draft blog post

Submit to CRAN:

• [x] usethis::use_version('major')
• [x] devtools::submit_cran()
• [x] Approve email

Wait for CRAN...

• [x] Accepted :tada:
• [x] usethis::use_github_release()
• [x] usethis::use_dev_version()
• [x] Finish blog post
• [x] Tweet
• [x] Add link to blog post in pkgdown news menu