Release: Add poetry.lock to sdist (#2405)

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# Rationale for this change
This PR explicitly add `poetry.lock` to the source distribution artifact
so that we can build and test RCs with pinned dependencies.

We want to pin dependencies because we verify a release candidate (RC)
by re-building the project from source distribution. We [unzip the
artifact](https://py.iceberg.apache.org/verify-release/#verifying-license-documentation),
[install the dependencies with `make install`, and then run
tests](https://py.iceberg.apache.org/verify-release/#testing).

Since `poetry.lock` is not automatically added to the source
distribution, `make install` will install packages only based on
`pyproject.toml`. The resolver will pull in the latest version by
default, which can lead to compatibility issues.
For example, in 0.10 RC2, we see that this pulled in the latest
datafusion which caused an compatibility issue with pyiceberg-core. This
is due to the breaking change in the FFI boundary, see
apache/datafusion-python#1217

Alternatively, we can restrict the upperbound of the dependencies, but
that since these are optional dependencies, we want to give users the
freedom to choose.

## Are these changes tested?

## Are there any user-facing changes?

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Author: kevinjqliu

pyproject.toml

@@ -46,6 +46,7 @@ include = [
   { path = "dev", format = "sdist" },
   { path = "pyiceberg/**/*.so", format = "wheel" },
   { path = "pyiceberg/**/*.pyd", format = "wheel" },
+  { path = "poetry.lock", format = "sdist" },
 ]
 
 [tool.poetry.dependencies]