General updates from package development workshop

[eroten]

New features

• fetch_county_geos() uses {tigris} to create an sf object. It takes one argument, core, which indicates whether to include only the core 7-county metro or the 9-county MPO area.
• Input checks using {rlang}
• New vignette detailing helpers for accessing spatial data, including snippets.
• New contributor guidelines.
• council_theme() is officially deprecated. Function will return error with message
• Improved testing
  • Package now uses {httr2} to access DB credentials securely. If you want to develop and test the package, you must contact @eroten for the COUNCILR_KEY to decrypt.
  • Added testing for colors

Dependency changes

• {tigris}, {cli}, {httr2} added
• {repmis} removed

General updates

• More uniform documentation standards
• RMarkdown template
  • New default text in RMarkdown template
  • Remove {repmis} and use integrated {knitr} function to fetch package dependencies.

closes #19

Checklist

First release:

• [x] usethis::use_cran_comments()
• [x] Update (aspirational) install instructions in README
• [x] Proofread Title: and Description:
• [x] Check that all exported functions have @return and @examples
• [x] Check that Authors@R: includes a copyright holder (role 'cph')
• [x] Check licensing of included files
• [x] Review https://github.com/DavisVaughan/extrachecks

Prepare for release:

• [x] git pull
• [x] devtools::build_readme()
• [x] urlchecker::url_check()
• [x] devtools::check(remote = TRUE, manual = TRUE)
• [x] devtools::check_win_devel()
• [x] rhub::check_for_cran()
• [x] git push