Update `tracing-subscriber` optional dependency

[jsdanielh]

Description

Update tracing-subscriber optional dependency from version 0.2 to version 0.3.

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Before we can merge this PR, please make sure that all the following items have been checked off. If any of the checklist items are not applicable, please leave them but write a little note why.

• [X] Targeted PR against correct branch (master)
• [X] Linked to Github issue with discussion and accepted design OR have an explanation in the PR that describes this work.
• [ ] Wrote unit tests. -- N/A (dependency upgrade)
• [ ] Updated relevant documentation in the code -- N/A (dependency upgrade)
• [X] Added a relevant changelog entry to the Pending section in CHANGELOG.md
• [X] Re-reviewed Files changed in the Github PR explorer