Backport changes from release/2.9

[StephenSorriaux]

Why is this needed?

• bump the version
• update changelog
• backport the fix that overrides the egg_info tag-build configuration

Proposed Changes

• bump version to 2.9.0
• add changelog for 2.9.0
• add some flags to build module to override tag-build value from setup.cfg

Does this PR introduce any breaking change?

No

[codecov-commenter]

Codecov Report

Base: 94.49% // Head: 94.40% // Decreases project coverage by -0.09% :warning:

Coverage data is based on head (c0ac67f) compared to base (161c687). Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #674 +/- ## ========================================== - Coverage 94.49% 94.40% -0.10% ========================================== Files 57 57 Lines 8399 8399 ========================================== - Hits 7937 7929 -8 - Misses 462 470 +8 ``` | [Impacted Files](https://codecov.io/gh/python-zk/kazoo/pull/674?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=python-zk) | Coverage Δ | | |---|---|---| | [kazoo/version.py](https://codecov.io/gh/python-zk/kazoo/pull/674/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=python-zk#diff-a2F6b28vdmVyc2lvbi5weQ==) | `100.00% <100.00%> (ø)` | | | [kazoo/tests/test\_cache.py](https://codecov.io/gh/python-zk/kazoo/pull/674/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=python-zk#diff-a2F6b28vdGVzdHMvdGVzdF9jYWNoZS5weQ==) | `57.48% <0.00%> (-2.39%)` | :arrow_down: | | [kazoo/protocol/connection.py](https://codecov.io/gh/python-zk/kazoo/pull/674/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=python-zk#diff-a2F6b28vcHJvdG9jb2wvY29ubmVjdGlvbi5weQ==) | `96.08% <0.00%> (-0.42%)` | :arrow_down: | | [kazoo/recipe/barrier.py](https://codecov.io/gh/python-zk/kazoo/pull/674/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=python-zk#diff-a2F6b28vcmVjaXBlL2JhcnJpZXIucHk=) | `100.00% <0.00%> (+1.03%)` | :arrow_up: | 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=python-zk). 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=python-zk)

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