address hashlib / openssl removal of ripemd160

[fselmo]

It seems like the new openssl version removed ripemd160 and we were relying on it via the hashlib dependency. We should figure out how to properly resolve this.

This is responsible for the recent failing tests on master.

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edit: It seems like this will be added back into default eventually, as noted here. Not sure how long this will take. Perhaps it's best to xfail the tests for now until they start passing again? 🤔