Unfortunately, since the new ecdsa library has a different interface and slightly different inner workings compared to the old PyECC library, the changes to support this update are not trivial. Luckily the ecdsa library is extensible enough to allow us to adjust the library's functionality with function parameters rather than monkey-patching, as we were doing with the previous version of the code. All of these interface changes are in addition to the normal rote Python 3 updates. This was tested by running a build with and without this patch and ensuring there were no unexpected diffs.
Differential Revision: https://phabricator.services.mozilla.com/D70117
