flat-cache - updating readme with serialize and deserialize

[jaredwray]

Please check if the PR fulfills these requirements

• [x] Followed the Contributing guidelines.
• [x] Tests for the changes have been added (for bug fixes/features) with 100% code coverage.
• [ ] Docs have been added / updated (for bug fixes / features)

What kind of change does this PR introduce? (Bug fix, feature, docs update, ...) flat-cache - updating readme with serialize and deserialize

[codecov[bot]]

Codecov Report

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

Project coverage is 100.00%. Comparing base (6e45c9e) to head (5887f09). Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #879 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 6 6 Lines 67 67 ========================================= Hits 67 67 ```

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