Add max-worker-lifetime-delta to docs

[ProgHaj]

I found max-worker-lifetime-delta had been added, but found no trace of it in the Options.rst

• https://github.com/unbit/uwsgi/pull/2021/files
• https://github.com/unbit/uwsgi/issues/2020
• https://github.com/unbit/uwsgi/blob/master/core/master_checks.c
• https://github.com/unbit/uwsgi/blob/master/core/uwsgi.c

[IamPecker]

您的邮件我已收到，我将会尽快给您回复信息。