Self-limiters

What's Changed
- Doubles the default connection pool size from 15 to 30
- Drops support for Python 3.8
- Fixes `Semaphore` issue where connection pool limits could lead to a deadlock
- Simplifies internals and improves logging

**Full Changelog**: https://github.com/sondrelg/self-limiters/compare/v0.3.0...v0.4.0

What's Changed
* Add connection pooling by sondrelg in https://github.com/sondrelg/self-limiters/pull/28


**Full Changelog**: https://github.com/sondrelg/self-limiters/compare/v0.2.0...v0.3.0

What's Changed
* Makes Semaphore expiry configurable (https://github.com/sondrelg/self-limiters/pull/27)
* Fixes Semaphore expiry issue which would break the Semaphore after 30 seconds of inactivity (https://github.com/sondrelg/self-limiters/pull/27)


**Full Changelog**: https://github.com/sondrelg/self-limiters/compare/v0.1.3...v0.2.0

What's Changed
* Coverage by sondrelg in https://github.com/sondrelg/self-limiters/pull/23
* refactor: Combine match statements by sondrelg in https://github.com/sondrelg/self-limiters/pull/25
* refactor: Replace create semaphore script by sondrelg in https://github.com/sondrelg/self-limiters/pull/26

Updates classifiers, docs, and improves semaphore performance a little by using pipelined queries over a Lua script for the semaphore release.

**Full Changelog**: https://github.com/sondrelg/self-limiters/compare/v0.1.2...v0.1.3

Removes `--frozen` maturin flag

Inlines Lua scripts. v0.1.0 didn't package these correctly.


**Full Changelog**: https://github.com/sondrelg/self-limiters/compare/v0.1.0...v0.1.1