Automate CRAN releases v2

Goals, and how achieved

1. Avoid conflicts in NEWS.md and DESCRIPTION
   • Bumping to CRAN version and back to dev version is atomic, no dangling release branch
   • Support for subsequent release attempts off of a branch created from a tag
2. Easy to undo a release attempt
   • Pre-flight with plan_release("pre-patch"), including grooming of NEWS.md
   • Caveat: once committed to a release, there is no way back, to avoid conflicts
3. More rigorous checks before release
   • On GitHub Actions for branches that start with cran-
   • Locally through urlchecker::url_update(), devtools::check_win_devel(), and rhub::check_for_cran()
   • TODO: Compatibility with usethis::use_release_issue()
4. Minimize interactive wait time
   • Checks run on GitHub Actions for branches that start with cran-
   • TODO: Use background jobs via job::empty() where useful
5. Compatibility with auto-merge and merge queues
   • GHA workflow
   • Commits/merges made by fledge are not newsworthy
6. Support merge and squash commits
   • We can always create a tag
   • PR merge is triggered by user
7. Support for dev version header
   • TODO: Composable workflow, grooming can be separate from release
8. Compatibility with manual release workflow
   • plan_release("pre-patch")
9. Consistency with usethis::use_release_issue()
   • TODO: snapshot tests for usethis:::release_checklist(), maintain own list

Non-goals

1. Always release from main branch
   • Conflicts with important goal to avoid conflicts, and also with auto-merge and merge queues
   • Release from main branch possible in some cases

Workflow

1. Optional, recommended because grooming the NEWS often gives a hint about what’s missing in a release:

   • fledge::plan_release("pre-patch") (or "pre-minor" or "pre-major")

   • Edit NEWS.md as needed

   • Perform any release-related tasks

   • Merge PR

2. Mandatory:

   • fledge::plan_release("next") (or "minor" or "major")

   • Perform work from previous step if omitted

   • fledge::release() (FIXME: also by merging PR)

3. If submission rejected:

   • fledge::plan_release("last") (FIXME)

   • Apply hotfixes required to submit

   • fledge::release() (FIXME: also by merging PR)

4. If submission abandoned:

   • No action required