Bump sella from 2.3.5 to 2.4.2

Bumps [sella](https://github.com/zadorlab/sella) from 2.3.5 to 2.4.2.
- [Release notes](https://github.com/zadorlab/sella/releases)
- [Changelog](https://github.com/zadorlab/sella/blob/master/CHANGELOG.md)
- [Commits](zadorlab/sella@v2.3.5...v2.4.2)

---
updated-dependencies:
- dependency-name: sella
  dependency-version: 2.4.2
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

tests/requirements-newtonnet.txt

@@ -1,4 +1,4 @@
 newtonnet==1.1.1
 geodesic-interpolate @ git+https://github.com/virtualzx-nad/geodesic-interpolate.git
-sella==2.3.5
+sella==2.4.2
 numpy==1.26.4

tests/requirements-sella.txt

@@ -1 +1 @@
-sella==2.3.5
+sella==2.4.2