Update the AUTHORSHIP and Maintainers' Guides to reflect co-author contributions

[seisman]

See issue #3746 for context. Closes #3746.

This PR updates the AUTHORSHIP file and maintainers' guides to clarify that we consider co-authorship (e.g., PR reviews) when counting contributions. This is in line with what we're saying in AUTHORSHIP:

Our goal for this document is to establish guidelines for giving credit to
contributors for their work. To do so, we will attempt to define:

• Fair and diverse ways of providing recognition for contributors' efforts.
• Define contributions in a broad way: writing code and/or documentation, providing
  ideas, fostering the community, etc.

To consider co-authorship (PR reviews), we need to use the following command to count the contributions:

git shortlog -sne --group=author --group=trailer:co-authored-by

For comparison, the first 10 lines of git shortlog -sne's output are:

$ git shortlog -sne | head -n 10
  1131	Dongdong Tian <seisman.info@gmail.com>
   291	Yvonne Fröhlich <94163266+yvonnefroehlich@users.noreply.github.com>
   291	dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
   267	Wei Ji <23487320+weiji14@users.noreply.github.com>
   256	Leonardo Uieda <leouieda@gmail.com>
   192	Will Schlitzer <schlitzer90@gmail.com>
   132	Michael Grund <23025878+michaelgrund@users.noreply.github.com>
    68	Meghan Jones <meghanj@alum.mit.edu>
    33	Yao Jiayuan <coreman.seism@gmail.com>
    30	Meghan Jones <meghanj@hawaii.edu>

For git shortlog -sne --group=author --group=trailer:co-authored-by, the output is:

$ git shortlog -sne --group=author --group=trailer:co-authored-by | head -n 10
  1480	Dongdong Tian <seisman.info@gmail.com>
   616	Wei Ji <23487320+weiji14@users.noreply.github.com>
   425	Yvonne Fröhlich <94163266+yvonnefroehlich@users.noreply.github.com>
   291	dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
   267	Michael Grund <23025878+michaelgrund@users.noreply.github.com>
   258	Leonardo Uieda <leouieda@gmail.com>
   237	Will Schlitzer <schlitzer90@gmail.com>
   129	Meghan Jones <meghanj@alum.mit.edu>
    53	Yao Jiayuan <coreman.seism@gmail.com>
    45	Meghan Jones <meghanj@hawaii.edu>

These numbers are still different from the numbers on the GitHub contributors page (https://github.com/GenericMappingTools/pygmt/graphs/contributors), but see #3905.

[seisman]

Please note that we inconsistently used git shortlog vX.0.0...HEAD -sne and git shortlog HEAD...v0.4.0 -sne in the old versions.

In the new version, I've changed them to git shortlog vX.Y.Z..HEAD (tag before HEAD vs HEAD before tag, .. vs ...). Their differences are summaried below (from ChatGPT):

Command	Meaning	Use Case
git shortlog v0.14.0..HEAD	Commits in HEAD but not in v0.14.0	✅ Changes since the tag
git shortlog HEAD..v0.14.0	Commits in v0.14.0 but not in HEAD	🔄 Unusual — usually empty if HEAD is ahead
git shortlog v0.14.0...HEAD	Commits in v0.14.0 or HEAD, but not both (symmetric difference)	🔍 Compare diverged histories
git shortlog HEAD...v0.14.0	Same as above — order doesn’t matter	🔍 Same as above

The three-dot version doens't work well for patch releases like v0.14.1/v0.14.2.

[yvonnefroehlich]

Uhh, did not realize so far, that there are two and three dot versions 😅.

[seisman]

With PR #3905 merged, the output is:

$ git shortlog -sne --group=author --group=trailer:co-authored-by | head -n 15
  1489	Dongdong Tian <seisman.info@gmail.com>
   627	Wei Ji Leong <23487320+weiji14@users.noreply.github.com>
   427	Yvonne Fröhlich <94163266+yvonnefroehlich@users.noreply.github.com>
   293	Michael Grund <michael_grund@gmx.de>
   291	dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
   258	Leonardo Uieda <leouieda@gmail.com>
   237	Will Schlitzer <schlitzer90@gmail.com>
   203	Max Jones <14077947+maxrjones@users.noreply.github.com>
    55	Jiayuan Yao <coreman.seism@gmail.com>
    17	actions-bot <58130806+actions-bot@users.noreply.github.com>
    15	Liam Toney <38269494+liamtoney@users.noreply.github.com>
     7	yohaimagen <mayochay@gmail.com>
     5	Jing-Hui Tong <86273921+JingHuiTong@users.noreply.github.com>
     3	Andre L. Belem <andrebelem@id.uff.br>
     3	Tyler Newton <54011699+tjnewton@users.noreply.github.com>

[weiji14]

Also need to update this line

pygmt/doc/maintenance.md

Line 259 in 662f97e

last release (e.g., use `git shortlog HEAD...v0.4.0 -sne`).

to use the two dot version.

[seisman]

Also need to update this line

pygmt/doc/maintenance.md

Line 259 in 662f97e

last release (e.g., use `git shortlog HEAD...v0.4.0 -sne`).

to use the two dot version.

It's already done (https://github.com/GenericMappingTools/pygmt/pull/3904/files)

[weiji14]

Oh yes it is, thanks!