move sphinx deps to python3
move sphinx deps to python3


Former-commit-id: 919167cfa9411a6ac99eac45eb75f71dbfe97e35 [formerly 2b07c9162cd3bfde9d8571d982b71aa26d8ff8d9]
Former-commit-id: 11bc48094efb290349f61a70a642fa0a67a6d3dc
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine