use `towncrier` to handle change log entries

[zacharyburnett]

this may not be needed for this project, but it's good to keep romanisim using the same infrastructure as romancal

[!TIP] For a public change, remember to write news fragment(s) in changes/:

• changes/<PR#>.apichange.rst: change to public API
• changes/<PR#>.bugfix.rst: fixes an issue
• changes/<PR#>.general.rst: infrastructure or miscellaneous change

Otherwise, add the label no-changelog-entry-needed.

[codecov[bot]]

Codecov Report

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

Project coverage is 89.24%. Comparing base (81028a8) to head (4f15158). Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #147 +/- ## ======================================= Coverage 89.24% 89.24% ======================================= Files 17 17 Lines 2073 2073 ======================================= Hits 1850 1850 Misses 223 223 ```

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