docs: add robertvolkmann as a contributor for code (#2292)

* docs: update README.md [skip ci]

* docs: update .all-contributorsrc [skip ci]

Co-authored-by: allcontributors[bot] <46447321+allcontributors[bot]@users.noreply.github.com>

allcontributors[bot] committed 3y ago

9dc91d8826a02a551a56ff5fe9dc566f1e426433

Parent: ae64433

Committed by GitHub <noreply@github.com> on 10/30/2022, 3:34:14 PM