Implement customizable serializer

[asvetlov]

Pre-requirement for taskiq-python/taskiq-pipelines#13

The main idea is:

1. JSONFormatter exists for the backward compatibility.
2. ProxyFormatter is used by default, which operates over broker.serializer API
3. The default serializer is JSONSerializer which is a thin wrapper around plain json.dumps() and json.loads()
4. TaskiqSerializer base class works with bytes, not str. The broker message type is a bytes anyway, plus formats like msgpack and cbor work with bytes anyway.

I can implement cbor and msgpack serializers as well if you are ok with optional dependencies (say, cbor2 is required only if a user explicitly imports taskiq.serializers.cbor_serializer:CBORSerializer.

[s3rius]

Now I see the point crystally clear. These changes will create a simpler API for defining your own serializers. Thank you very much.

I'm totally ok with optional dependencies. In the next iteration I was planning to add a lot of optional depndencies to make installation process easier.

[s3rius]

To fix mypy please consider running poetry update.

To fix failing tests, make them async and mark with pytest.mark.anyio. This problem happens because we create a semaphore in InmemoryBroker. This works in py3.10 and above, but doesn't work for older versions. We will fix it.

[asvetlov]

tests should be green now, at least locally I don't see any problem

[codecov-commenter]

Codecov Report

Merging #214 (c198624) into develop (e66f3aa) will increase coverage by 5.65%.
Report is 131 commits behind head on develop.
The diff coverage is 73.28%.

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@@             Coverage Diff             @@
##           develop     #214      +/-   ##
===========================================
+ Coverage    67.62%   73.27%   +5.65%     
===========================================
  Files           37       51      +14     
  Lines          942     1553     +611     
===========================================
+ Hits           637     1138     +501     
- Misses         305      415     +110     

Files	Coverage Δ
taskiq/__init__.py	100.00% <100.00%> (ø)
taskiq/abc/formatter.py	100.00% <100.00%> (ø)
taskiq/abc/middleware.py	100.00% <ø> (ø)
taskiq/abc/result_backend.py	100.00% <ø> (ø)
taskiq/abc/schedule_source.py	100.00% <100.00%> (ø)
taskiq/abc/serializer.py	100.00% <100.00%> (ø)
taskiq/acks.py	100.00% <100.00%> (ø)
taskiq/api/__init__.py	100.00% <100.00%> (ø)
taskiq/cli/common_args.py	100.00% <100.00%> (ø)
taskiq/cli/watcher.py	0.00% <ø> (ø)
... and 37 more

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[s3rius]

Since these mypy problems are totally minor, we can merge it now. I'll fix it later.

[s3rius]

Thank you very much for your contribution.

[asvetlov]

You are welcome! The next step is PR for taskiq-pipelines

[asvetlov]

Could you please consider publishing a new release?

It is a pre-requirement for conversion taskiq-pipelines to use new serializers.

[s3rius]

Sure.

[s3rius]

Changes available in https://github.com/taskiq-python/taskiq/releases/tag/0.9.3.