Add check of undocumented arguments to the release process

Summary: As per title

Test Plan:
Read the release-process.md docuemnt
Ensure there is a line regarding checking the arguments and that this
line is set at the correct location in the document.

Reviewers: #bitcoin_abc, deadalnix, Mengerian

Reviewed By: #bitcoin_abc, deadalnix, Mengerian

Subscribers: teamcity, schancel

Differential Revision: https://reviews.bitcoinabc.org/D2292