avoid shapely.vectorized

[mathause]

• [ ] Closes #xxx
• [ ] Tests added
• [ ] Passes isort . && black . && flake8
• [ ] Fully documented, including whats-new.rst

Avoids shapely.verctorized which may be removed in the future shapely/shapely/issues/1630. In shapely v2 this is no longer faster/ optimized.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 100.00%. Comparing base (d4e4ab7) to head (17275aa). Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #554 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 16 16 Lines 1314 1313 -1 ========================================= - Hits 1314 1313 -1 ``` | [Flag](https://app.codecov.io/gh/regionmask/regionmask/pull/554/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=regionmask) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/regionmask/regionmask/pull/554/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=regionmask) | `100.00% <100.00%> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=regionmask#carryforward-flags-in-the-pull-request-comment) to find out more.

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