Refactor deprecated randomNonce() with Salter().qb64

[rubelhassan]

Issue keripy #739

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 92.83%. Comparing base (caad67b) to head (62b6ad0). Report is 7 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #241 +/- ## ========================================== + Coverage 92.82% 92.83% +0.01% ========================================== Files 37 37 Lines 6982 6995 +13 ========================================== + Hits 6481 6494 +13 Misses 501 501 ```

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