Draft 13 key rollover compatibility

My tests show this approach should work :+1: - Sign in to GitHub · GitHub

=== RUN   TestKeyRollover
=== RUN   TestKeyRollover/Missing_account_URL
=== RUN   TestKeyRollover/Missing_new_key_from_inner_payload
=== RUN   TestKeyRollover/New_key_is_the_same_as_the_old_key
=== RUN   TestKeyRollover/Inner_JWS_signed_by_the_wrong_key
=== RUN   TestKeyRollover/Valid_key_rollover_request,_key_exists
=== RUN   TestKeyRollover/Valid_key_rollover_request
=== RUN   TestKeyRollover/Valid_key_rollover_request,_added_ACME13KeyRollover_compat
=== RUN   TestKeyRollover/ACME13KeyRollover,_legacy_rollover_request
=== RUN   TestKeyRollover/ACME13KeyRollover,_Missing_account_URL
=== RUN   TestKeyRollover/ACME13KeyRollover,_incorrect_old_key
=== RUN   TestKeyRollover/ACME13KeyRollover,_Valid_key_rollover_request,_key_exists
=== RUN   TestKeyRollover/ACME13KeyRollover,_Valid_key_rollover_request
=== RUN   TestKeyRollover/ACME13KeyRollover,_Valid_key_rollover_request,_legacy_compat
--- PASS: TestKeyRollover (1.25s)
    --- PASS: TestKeyRollover/Missing_account_URL (0.04s)
    --- PASS: TestKeyRollover/Missing_new_key_from_inner_payload (0.04s)
    --- PASS: TestKeyRollover/New_key_is_the_same_as_the_old_key (0.06s)
    --- PASS: TestKeyRollover/Inner_JWS_signed_by_the_wrong_key (0.05s)
    --- PASS: TestKeyRollover/Valid_key_rollover_request,_key_exists (0.05s)
    --- PASS: TestKeyRollover/Valid_key_rollover_request (0.05s)
    --- PASS: TestKeyRollover/Valid_key_rollover_request,_added_ACME13KeyRollover_compat (0.05s)
    --- PASS: TestKeyRollover/ACME13KeyRollover,_legacy_rollover_request (0.04s)
    --- PASS: TestKeyRollover/ACME13KeyRollover,_Missing_account_URL (0.04s)
    --- PASS: TestKeyRollover/ACME13KeyRollover,_incorrect_old_key (0.04s)
    --- PASS: TestKeyRollover/ACME13KeyRollover,_Valid_key_rollover_request,_key_exists (0.05s)
    --- PASS: TestKeyRollover/ACME13KeyRollover,_Valid_key_rollover_request (0.05s)
    --- PASS: TestKeyRollover/ACME13KeyRollover,_Valid_key_rollover_request,_legacy_compat (0.05s)
PASS
ok  	github.com/letsencrypt/boulder/wfe2	(cached)