Bump polars from 0.18.13 to 0.18.15 (#583)

Bumps [polars](https://github.com/pola-rs/polars) from 0.18.13 to
0.18.15.
<details>
<summary>Commits</summary>
<ul>
<li><a
href="https://github.com/pola-rs/polars/commit/03571770bdaefdd37180e12034f3054973b89bc6"><code>0357177</code></a>
fix(rust, python): rollback cse in groupby: python 0.18.15 (<a
href="https://redirect.github.com/pola-rs/polars/issues/10491">#10491</a>)</li>
<li><a
href="https://github.com/pola-rs/polars/commit/11b7583cf8e4a3bb5f23d50303b853ba34bfb77c"><code>11b7583</code></a>
test(python): Mark import timing check as slow (<a
href="https://redirect.github.com/pola-rs/polars/issues/10487">#10487</a>)</li>
<li><a
href="https://github.com/pola-rs/polars/commit/436bcf71de7af2fbae5e901d3bec10516b5fdb11"><code>436bcf7</code></a>
test(python): Gather all streaming tests (<a
href="https://redirect.github.com/pola-rs/polars/issues/10485">#10485</a>)</li>
<li><a
href="https://github.com/pola-rs/polars/commit/54831c110dcd64e7fffcabd3cb5afbbd78745bca"><code>54831c1</code></a>
build(python): Bump <code>maturin</code> to version 1.2.1 (<a
href="https://redirect.github.com/pola-rs/polars/issues/10479">#10479</a>)</li>
<li><a
href="https://github.com/pola-rs/polars/commit/ec0c91f93fcd1ac355c667d6c3c3f30b257ea0a6"><code>ec0c91f</code></a>
rust polars 0.32.0; python polars 0.18.14 (<a
href="https://redirect.github.com/pola-rs/polars/issues/10474">#10474</a>)</li>
<li><a
href="https://github.com/pola-rs/polars/commit/99af5f126e2572e63e4363541e8544050e5d5ecb"><code>99af5f1</code></a>
docs(python): add <code>vertical_relaxed</code> example for
<code>pl.concat</code> (<a
href="https://redirect.github.com/pola-rs/polars/issues/10472">#10472</a>)</li>
<li><a
href="https://github.com/pola-rs/polars/commit/e73743a843450aed04150ddbe45db9837e18be34"><code>e73743a</code></a>
feat(rust, python): quote style option for csv writer (<a
href="https://redirect.github.com/pola-rs/polars/issues/10422">#10422</a>)</li>
<li><a
href="https://github.com/pola-rs/polars/commit/8eec7188736825875e2667ceb396466725a8aa03"><code>8eec718</code></a>
fix(python): fix pyarrow write_to_dataset wrt check_not_directory
parameter (...</li>
<li><a
href="https://github.com/pola-rs/polars/commit/67e3148db268d1b5f086e2eed775dfe8e870da01"><code>67e3148</code></a>
feat(python, rust): add &quot;raise_if_empty&quot; flag to
<code>read_excel</code>, <code>read_csv</code>, `s...</li>
<li><a
href="https://github.com/pola-rs/polars/commit/4c677d8105a0cacfe2bcd7f71e427927c99bc720"><code>4c677d8</code></a>
feat(rust): be more permissive on predicate pushdown to left side of
left joi...</li>
<li>Additional commits viewable in <a
href="https://github.com/pola-rs/polars/compare/py-0.18.13...py-0.18.15">compare
view</a></li>
</ul>
</details>
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</details>

Author: llucax

pyproject.toml

@@ -54,7 +54,7 @@ dev-docstrings = [
   "darglint == 1.8.1",
   "tomli == 2.0.1",      # Needed by pydocstyle to read pyproject.toml
 ]
-dev-examples = ["polars == 0.18.13"]
+dev-examples = ["polars == 0.18.15"]
 dev-formatting = ["black == 23.7.0", "isort == 5.12.0"]
 dev-mkdocs = [
   "mike == 1.1.2",