[GRASS-git] [OSGeo/grass] 985642: contributing: release procedure updates (G83) (#3032)

[Markus Neteler]

  Branch: refs/heads/releasebranch_8_3
  Home:   https://github.com/OSGeo/grass
  Commit: 985642b0d664cb6d7d29175a7783ed40de518784
      https://github.com/OSGeo/grass/commit/985642b0d664cb6d7d29175a7783ed40de518784
  Author: Markus Neteler <neteler at osgeo.org>
  Date:   2023-06-20 (Tue, 20 Jun 2023)

  Changed paths:
    M doc/howto_release.md
    M doc/infrastructure.md

  Log Message:
  -----------
  contributing: release procedure updates (G83) (#3032)

- partial sync to document version in `main`
- markdown linting fixes
- some outdated version numbers updated
- fix path to helper script
- Use subsections; add Publish release section
- osgeo8-grass -> osgeo7-grass
- Merge in improvements from #2707 (replaces #2707)
- Attempt to merge in improvements from #2414

Note: PRs for the other branches will be created separately (do not back-/forward-port this PR).