Revert "Merge pull request #602 from oauthjs/renovate/sinon-9.x"
Revert "Merge pull request #602 from oauthjs/renovate/sinon-9.x"

This reverts commit 6997303460cfeb129d55496706fc1b213cd60504, reversing
changes made to b84778b317890f7082cde8effece18277abf61fc.

oauthjs/node-oauth2-server,visvk/node-oauth2-server