Bump pyiron-atomistics from 0.6.12 to 0.6.16

Bumps [pyiron-atomistics](https://github.com/pyiron/pyiron_atomistics) from 0.6.12 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-0.6.12...pyiron_atomistics-0.6.16)

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

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

setup.py

@@ -42,7 +42,7 @@
     extras_require={
         'atomistic': [
             'ase==3.23.0',
-            'pyiron_atomistics==0.6.12',
+            'pyiron_atomistics==0.6.16',
             'pycp2k==0.2.2',
         ],
         'fenics': [