No contributing, support, or code-of-conduct guidance

[schochastics]

JOSS asks for clear guidance on contributing, reporting problems, and seeking support. The
repository has no CONTRIBUTING.md, no CODE_OF_CONDUCT.md, and no issue templates.
BugReports: in DESCRIPTION points at the tracker, which covers part of the second point but not
the other two.

usethis::use_tidy_contributing() and usethis::use_code_of_conduct() generate reasonable
starting points. Worth saying explicitly in CONTRIBUTING.md: whether you want PRs against main,
whether contributors should run devtools::document() themselves, and where to ask usage questions
as opposed to filing bugs.

This is part of the review at openjournals/joss-reviews#11209

[castromaa]

We have added CONTRIBUTING.md via usethis::use_tidy_contributing() and CODE_OF_CONDUCT.md via usethis::use_code_of_conduct(). We adopted the Contributor Covenant open source code of conduct, and followed the tidyverse and R community CONTRIBUTING guidance in full.

(Revised in Version 1.5.4)

[schochastics]

.github/CONTRIBUTING.md (47 lines) and CODE_OF_CONDUCT.md (126 lines, Contributor Covenant) are now both present but there are some remaining gaps due to the fact that CONTRIBUTING.md
is the unmodified usethis::use_tidy_contributing() template:

• It instructs contributors to "add a bullet to the top of NEWS.md". There is no
  NEWS.md in this repository; the changelog lives in inst/NEWS.Rd in Rd format. A
  contributor following the file literally will not find the file to edit.
• It points at the tidyverse style guide and Air. The package does not follow tidyverse
  style. It uses camelCase S4 generics, 4-space indentation in most files, and base-R
  idiom throughout. Telling contributors to run Air on their PRs would produce diffs that
  conflict with the surrounding code.
• Support guidance is still missing. The third JOSS sub-item is "seeking support",
  as distinct from reporting bugs. Neither CONTRIBUTING.md nor the README says where to
  ask a usage question. One line pointing at GitHub Discussions, or saying explicitly that
  usage questions are welcome as issues, closes this.

[castromaa]

Thank you. We appreciate all the feedback and suggestions.

• We revised both CONTRIBUTING.md and CODE_OF_CONDUCT.md to address the remaining gaps.
• We also added a NEWS.md file and moved the changelog from inst/NEWS.Rd to NEWS.md, which is indeed more practical for contributors and for us.
• Finally, we added a new support section to the README that explains where users can ask usage questions.