Bump mix version to 0.10.3

[codecov[bot]]

Codecov Report

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

Comparison is base (5fcd3b5) 96.59% compared to head (889c8b9) 96.59%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #303 +/- ## ======================================= Coverage 96.59% 96.59% ======================================= Files 21 21 Lines 499 499 ======================================= Hits 482 482 Misses 17 17 ```

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