Exclude DVC files from source/binary distributions

[seisman]

Description of proposed changes

See #1086 for context.

This PR excludes all the *.dvc files from the source/binary distributions to reduce the tarball sizes. The source tarball size is reduced from 251K to 238K.

Fixes #

Reminders

• Run make format and make check to make sure the code follows the style guide.
• Add tests for new features or tests that would have caught the bug that you're fixing.
• Add new public functions/methods/classes to doc/api/index.rst.
• Write detailed docstrings for all functions/methods.
• If wrapping a new module, open a 'Wrap new GMT module' issue and submit reasonably-sized PRs.
• If adding new functionality, add an example to docstrings or tutorials.
• Use underscores (not hyphens) in names of Python files and directories.

Slash Commands

You can write slash commands (/command) in the first line of a comment to perform
specific operations. Supported slash commands are:

• /format: automatically format and lint the code
• /test-gmt-dev: run full tests on the latest GMT development version

[seisman]

Ping @weiji14 to have a final review since he is more experienced with DVC and python packaging.

[weiji14]

Probably should still archive the *.dvc files somewhere. Could you modify the release-basline-images.yml workflow to also save the *.dvc files on release? From #1317, it is only saving the *.png files, and not the *.dvc files.

[seisman]

Probably should still archive the *.dvc files somewhere.

These *.dvc files are still available in the source code tarballs created by GitHub releases (e.g., see https://github.com/GenericMappingTools/pygmt/releases/tag/v0.9.0).

[weiji14]

Probably should still archive the *.dvc files somewhere.

These *.dvc files are still available in the source code tarballs created by GitHub releases (e.g., see https://github.com/GenericMappingTools/pygmt/releases/tag/v0.9.0).

Ah yes, then should be ok then! Good to have a smaller source tarball on PyPI.