🚀 RELEASE: v0.3.1

[mmcky]

This PR sets up for the v0.3.1 release

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[codecov[bot]]

Codecov Report

Base: 91.06% // Head: 91.06% // No change to project coverage :thumbsup:

Coverage data is based on head (f9975ea) compared to base (530f0d5). Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #87 +/- ## ======================================= Coverage 91.06% 91.06% ======================================= Files 7 7 Lines 739 739 ======================================= Hits 673 673 Misses 66 66 ``` | Flag | Coverage Δ | | |---|---|---| | pytests | `91.06% <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=executablebooks#carryforward-flags-in-the-pull-request-comment) to find out more. | [Impacted Files](https://codecov.io/gh/executablebooks/sphinx-external-toc/pull/87?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=executablebooks) | Coverage Δ | | |---|---|---| | [sphinx\_external\_toc/\_\_init\_\_.py](https://codecov.io/gh/executablebooks/sphinx-external-toc/pull/87/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=executablebooks#diff-c3BoaW54X2V4dGVybmFsX3RvYy9fX2luaXRfXy5weQ==) | `92.85% <100.00%> (ø)` | | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=executablebooks). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=executablebooks)

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[welcome[bot]]

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