Migrate to bump-my-version, fix supported versions in README

[protoroto]

Description

Migrate to bump-my-version, fix supported versions in README

References

Fix #96

Checklist

• [x] I have read the contribution guide
• [x] Code lint checked via inv lint
• [x] changes file included (see docs)
• [ ] Usage documentation added in case of new features
• [ ] Tests added

[coveralls]

coverage: 100.0%. remained the same when pulling ed43946a4211f6884e4e47d488eedbdd4726539b on feature/issue-96-migrate-to-bump-my-version into ed74a547bbf97e8c158c2f8540d8382f377b8d17 on develop.

[codecov[bot]]

Codecov Report

All modified lines are covered by tests :white_check_mark:

Comparison is base (ed74a54) 100.00% compared to head (ed43946) 100.00%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #97 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 9 9 Lines 152 152 Branches 19 19 ========================================= Hits 152 152 ``` | [Flag](https://app.codecov.io/gh/nephila/djangocms-page-sitemap/pull/97/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=nephila) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/nephila/djangocms-page-sitemap/pull/97/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=nephila) | `100.00% <ø> (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=nephila#carryforward-flags-in-the-pull-request-comment) to find out more.

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