CI: Configure workflows to run on 'workflow_dispatch' event

[seisman]

Description of proposed changes

Inspired by the comment #2910 (comment).

Sometimes we want to trigger a workflow to see if everything still works. This can be done by configuring workflows to run on the workflow_dispatch event.

The benchmarks.yml workflow is already configured with workflow_dispatch event. To manually trigger a run, go to https://github.com/GenericMappingTools/pygmt/actions/workflows/benchmarks.yml and click the "Run workflow" button on the right.

This enable configures more workflows to run on wotkflow_dispatch event. Below is a list of workflows that will support manual triggering after this PR.

• benchmarks.yml
• cache_data.yaml
• check-links.yml
• ci_docs.yml
• ci_doctests.yaml
• ci_tests_dev.yaml
• ci_tests_legacy.yaml
• ci_tests.yaml
• dvc-diff.yml
• format-command.yml
• publish-to-pypi.yml
• release-baseline-images.yml
• release-drafter.yml
• slash-command-dispatch.yml
• style_checks.yaml
• type_checks.yml

Reference: https://docs.github.com/en/actions/using-workflows/manually-running-a-workflow

[weiji14]

Yep, makes sense to add workflow_dispatch to these CI workflows. Just some sentence rewording suggestions.