Bump pyiron-atomistics from 0.6.15 to 0.6.16

Bumps [pyiron-atomistics](https://github.com/pyiron/pyiron_atomistics) from 0.6.15 to 0.6.16.
- [Release notes](https://github.com/pyiron/pyiron_atomistics/releases)
- [Changelog](https://github.com/pyiron/pyiron_atomistics/blob/main/CHANGELOG.md)
- [Commits](pyiron/pyiron_atomistics@pyiron_atomistics-0.6.15...pyiron_atomistics-0.6.16)

---
updated-dependencies:
- dependency-name: pyiron-atomistics
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

requirements.txt

@@ -1,3 +1,3 @@
 nglview==3.1.2
 pyiron==0.5.2
-pyiron_atomistics==0.6.15
+pyiron_atomistics==0.6.16