CURL command to set system watchdog

Following is the command to get system watchdog timeout value

sudo curl -sS --unix-socket /run/snapd.socket http://snapd/v2/snaps/system/conf -X GET -d '{"watchdog"}'
{"type":"sync","status-code":200,"status":"OK","result":{"cloud":{"name":"unknown"},"seed":{"loaded":true},"watchdog":{"runtime-timeout":"3m","shutdown-timeout":"8m"}}}

Looking for CURL command to set system watchdog runtime timeout. I have tried -

sudo curl -sS --unix-socket /run/snapd.socket http://snapd/v2/snaps/system/conf -X POST -d '{"watchdog": {"runtime-timeout":"4m"}}'

but I get

{"type":"error","status-code":405,"status":"Method Not Allowed","result":{"message":"method \"POST\" not allowed"}}

@pedronis any pointers?

After some trials got the command (needed to use PUT instead of POST):

sudo curl -sS --unix-socket /run/snapd.socket http://snapd/v2/snaps/system/conf -X PUT -d '{"watchdog.runtime-timeout": "5m"}'