pkgdown fixes, DEVELOPMENT release notes

[dsweber2]

Checklist

Please:

• Make sure this PR is against "dev", not "main" (unless this is a release
  PR).
• Request a review from one of the current epidatr main reviewers:
  brookslogan, dshemetov, nmdefries, dsweber2.
• Makes sure to bump the version number in DESCRIPTION. Always increment
  the patch version number (the third number), unless you are making a
  release PR from dev to main, in which case increment the minor version
  number (the second number). NA, it's CI/docs only
• Describe changes made in NEWS.md, making sure breaking changes
  (backwards-incompatible changes to the documented interface) are noted.
  Collect the changes under the next release number (e.g. if you are on
  1.7.2, then write your changes under the 1.8 heading). NA, it's CI/docs only

Change explanations for reviewer

We found a number of things to fix in the process of moving this process over to epiprocess. This is a mergeback of those updates (specifically cmu-delphi/epiprocess#425 and cmu-delphi/epiprocess#428)

Magic GitHub syntax to mark associated Issue(s) as resolved when this is merged into the default branch