Asf-tools

Changed
- Upgraded the `reusable-mypy` action to [v0.15.0](https://github.com/ASFHyP3/actions/releases/tag/v0.15.0).

Added
- Add `mypy` to [`static-analysis`](.github/workflows/static-analysis.yml)

Fixed
- The [`release`](.github/workflows/release.yml) Github Actions workflow now uses the `gh` CLI instead of the archived `repo-sync/pull-request` action.

Changed
- The [`static-analysis`](.github/workflows/static-analysis.yml) Github Actions workflow now uses `ruff` rather than `flake8`.

Removed
- Support for Python 3.8 and 3.9 has been removed.

Fixed
- Changed relative link to the watermasking readme in the repo readme to the full URL, so that the link is valid when readme content is mirrored in hyp3-docs

Added
- A description of the `asf_tools.watermasking` sub-package has been added to the [`asf_tools` README](src/asf_tools/README.md)
- Installation instructions for `osmium-tool` have been added to the [`asf_tools.watermasking` README](src/asf_tools/watermasking/README.md)

Fixed
- `osmium-tool` dependency handling. Because `osmium-tool` is not distributed on PyPI and thus is not installed when `pip` installing `asf_tools`, `asf_tools` will now raise an `ImportError` when `osmium-tool` is missing that provides installation instructions. Note: `osmium-tool` is distributed on conda-forge and will be included when conda installing `asf_tools`.