Updated CONTRIBUTORS.txt [skip CI]
Updated CONTRIBUTORS.txt [skip CI]


Former-commit-id: de0fbb73e5a7f350409fc295b2b857b417ccfe39 [formerly 296324ba3a8ce80578e9d85ceb3a83207f25b4ec]
Former-commit-id: 74d857da5c98228d13264abc7a46167952d91a4b
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine