Major bump of tracing-subscriber version (#3891)

I don't think there are any more releases to the 0.2.x versions, so best
we're on the 0.3.x release.

No change on the benchmarks, fast local time is still just as fast as
before:

new version bench:
```
fast_local_time         time:   [30.551 ns 30.595 ns 30.668 ns]
```

old version bench:
```
fast_local_time         time:   [30.598 ns 30.646 ns 30.723 ns]
```

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Co-authored-by: Bastian Köcher <[email protected]>