Release PyGMT v0.20.0

**Release**: [v0.20.0](https://github.com/GenericMappingTools/pygmt/milestone/28)
**Scheduled Date**: 2026/09/30
**Pull request due date**: 20YY/MM/DD
**DOI**: `10.5281/zenodo.XXXXXXX`
**Announcement draft**: https://hackmd.io/@pygmt/xxxxxxxx

**Priority PRs/issues to complete prior to release**

- [ ] Wrap X ()
- [ ] Wrap Y ()

**Before release**:

- [ ] Reserve a DOI on [Zenodo](https://zenodo.org) by clicking on "New Version"
- [ ] Check [SPEC 0](https://scientific-python.org/specs/spec-0000/) to see if we need to bump the minimum supported versions of GMT, Python and core package dependencies (NumPy, pandas, xarray)
- [ ] Review the ["PyGMT Team" page](https://www.pygmt.org/dev/team.html)
- [ ] README looks good on TestPyPI. Visit [TestPyPI](https://test.pypi.org/project/pygmt/#history), click the latest pre-release, and check the homepage.
- [ ] Review new parameter names added/changed for clarity and consistency across the API
- [ ] Check to ensure that:
- [ ] Deprecated workarounds/codes/tests are removed. Run `grep -r "# TODO" --include="*.py" .` to find all potential TODOs.
- [ ] All tests pass in the ["GMT Legacy Tests" workflow](https://github.com/GenericMappingTools/pygmt/actions/workflows/ci_tests_legacy.yaml)
- [ ] All tests pass in the ["GMT Dev Tests" workflow](https://github.com/GenericMappingTools/pygmt/actions/workflows/ci_tests_dev.yaml)
- [ ] All tests pass in the ["Doctests" workflow](https://github.com/GenericMappingTools/pygmt/actions/workflows/ci_doctests.yaml)
- [ ] All links work in the ["Check Links" workflow](https://github.com/GenericMappingTools/pygmt/actions/workflows/check-links.yml)
- [ ] Update warnings in `pygmt/_show_versions.py` as well as notes in [Not working transparency](https://www.pygmt.org/dev/install.html#not-working-transparency) regarding GMT-Ghostscript incompatibility
- [ ] Finish up the "Changelog entry for v0.x.x" Pull Request (Use the previous changelog PR as a reference)
- [ ] Run `make spellcheck` to check common misspellings. If there are any, either fix them or add them to the relevant spelling configuration in `pyproject.toml`
- [ ] Draft the announcement on https://hackmd.io/@pygmt

**Release**:

- [ ] At the [PyGMT release page on GitHub](https://github.com/GenericMappingTools/pygmt/releases):
- [ ] Edit the draft release notes with the finalized changelog
- [ ] Set the tag version and release title to vX.Y.Z
- [ ] Make a release by clicking the 'Publish Release' button, this will automatically create a tag too
- [ ] Verify that [all workflows triggered by the release](https://github.com/GenericMappingTools/pygmt/actions?query=event%3Arelease) pass
- [ ] The latest version is correct on [PyPI](https://pypi.org/project/pygmt/)
- [ ] The latest version is correct on https://www.pygmt.org/latest/
- [ ] The [release page](https://github.com/GenericMappingTools/pygmt/releases) has five assets, including `baseline-images.zip`, `pygmt-docs.zip` and `pygmt-docs.pdf`
- [ ] Upload to Zenodo:
- [ ] Download pygmt-X.Y.Z.zip (listed as Source code (zip); rename it to pygmt-vX.Y.Z.zip) and baseline-images.zip from the release page, and upload the two zip files to https://zenodo.org/deposit
- [ ] Ensure they are filed under the correct reserved DOI
- [ ] Update authorship information based on `CITATION.cff`

**After release**:

- [ ] Update conda-forge [pygmt-feedstock](https://github.com/conda-forge/pygmt-feedstock) (Done automatically by conda-forge's bot. If you don't want to wait, open a new issue in the `conda-forge/pygmt-feedstock` repository with the title `@conda-forge-admin, please update version`. This will trigger the bot immediately. Remember to pin GMT, Python and SPEC0 versions)
- [ ] Bump PyGMT version on https://github.com/GenericMappingTools/try-gmt (after conda-forge update)
- [ ] Announce the release on:
- [ ] GMT [forum](https://forum.generic-mapping-tools.org/c/news/) (do this announcement first! Requires moderator status)
- [ ] [ResearchGate](https://www.researchgate.net) (after forum announcement; download the ZIP file of the new release from Zenodo and add it as research item via the **code** category, be sure to include the corresponding new Zenodo DOI)
- [ ] Update release checklist template with any additional bullet points that may have arisen during the release

---

- [ ] Party :tada: (don't tick before all other checkboxes are ticked!)

Start with the v0.20.0 milestone and work through the checklist, including the GitHub release page, TestPyPI, Zenodo, and the linked CI workflows. Review pygmt/_show_versions.py, the installation notes, CITATION.cff, pyproject.toml, and the changelog PR where listed. Done means the release, workflows, package and documentation checks, Zenodo upload, announcements, and follow-up updates are complete.

Written by the indexing model from the issue text.