feat: Extend allowed_values option of JSONSchema for Property(ArrayType)

[TyShkan]

Closes #1600 (what a number! 🎉)

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📚 Documentation preview 📚: https://meltano-sdk--1602.org.readthedocs.build/en/1602/

[codecov]

Codecov Report

Merging #1602 (7b2520b) into main (21d0a14) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main    #1602   +/-   ##
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  Coverage   86.18%   86.18%           
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  Files          58       58           
  Lines        4747     4750    +3     
  Branches      797      798    +1     
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+ Hits         4091     4094    +3     
  Misses        465      465           
  Partials      191      191           

Impacted Files	Coverage Δ
singer_sdk/typing.py	94.92% <100.00%> (+0.07%)	⬆️

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[edgarrmondragon]

Hey @TyShkan, thanks for the PR!

The main problem I see with this approach is that it prohibits adding those extra properties to the wrapping ArrayType. Think of these two samples:

{"type": "array", "items": {"type": "string", "enum": ["a", "b"]}}

and

{"type": "array", "items": {"type": "string"}, "enum": [["a", "b"], ["b", "c"]]}

Both are valid, but the second one can't be constructed. I have a solution using a modified descriptor and will open a PR in a few.

EDIT: #1603

[TyShkan]

@edgarrmondragon Yep! That makes sense, the solution works great and definitely much more flexible. Thanks! Would be great to see it in the next version (: