Would be nice to have better install instructions!
Right now I try to setup workflow webhooks, as below, and tried setting both Content-Type options

but still getting errors:
INFO: 140.82.115.58:0 - "POST / HTTP/1.1" 405 Method Not Allowed
INFO: 140.82.115.44:0 - "POST / HTTP/1.1" 405 Method Not Allowed
INFO: 140.82.115.60:0 - "POST / HTTP/1.1" 405 Method Not Allowed
INFO: 140.82.115.156:0 - "POST / HTTP/1.1" 405 Method Not Allowed
INFO: 140.82.115.31:0 - "POST / HTTP/1.1" 405 Method Not Allowed