Prepare for release user_events_metrics exporter 0.3.0

[cijothomas]

Prepare changelog and version to release user_events metrics exporter. I think there should be a release done for all other crates as well.

Merge requirement checklist

• [ ] CONTRIBUTING guidelines followed
• [ ] Unit tests added/updated (if applicable)
• [ ] Appropriate CHANGELOG.md files updated for non-trivial, user-facing changes
• [ ] Changes in public API reviewed (if applicable)

[codecov[bot]]

Codecov Report

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

Project coverage is 50.6%. Comparing base (6b30502) to head (482cd94).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #40 +/- ## ===================================== Coverage 50.6% 50.6% ===================================== Files 30 30 Lines 4287 4287 ===================================== Hits 2171 2171 Misses 2116 2116 ```

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