Bump plotnine from 0.15.3 to 0.15.7 in the python-dependencies group

Bumps the python-dependencies group with 1 update: [plotnine](https://github.com/has2k1/plotnine).


Updates `plotnine` from 0.15.3 to 0.15.7
- [Release notes](https://github.com/has2k1/plotnine/releases)
- [Changelog](https://github.com/has2k1/plotnine/blob/v0.15.7/doc/changelog.qmd)
- [Commits](has2k1/plotnine@v0.15.3...v0.15.7)

---
updated-dependencies:
- dependency-name: plotnine
  dependency-version: 0.15.7
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: python-dependencies
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

pyproject.toml

@@ -17,7 +17,7 @@ dependencies = [
     # Plotting libraries
     "matplotlib>=3.7",
     "seaborn>=0.13",
-    "plotnine>=0.13",
+    "plotnine>=0.15.7",
     "lets-plot>=4.11",
     "plotly>=5.24",
     "altair>=5.0",