ensure zipkin tags and attributes are cast to strings

[brettmc]

Closes: #1404

[netlify[bot]]

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[codecov[bot]]

Codecov Report

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

Project coverage is 73.77%. Comparing base (2c1da9a) to head (f6030dd). Report is 1 commits behind head on main.

Additional details and impacted files

[](https://app.codecov.io/gh/open-telemetry/opentelemetry-php/pull/1406?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry) ```diff @@ Coverage Diff @@ ## main #1406 +/- ## ============================================ + Coverage 73.68% 73.77% +0.09% Complexity 2682 2682 ============================================ Files 387 387 Lines 7672 7672 ============================================ + Hits 5653 5660 +7 + Misses 2019 2012 -7 ``` | [Flag](https://app.codecov.io/gh/open-telemetry/opentelemetry-php/pull/1406/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry) | Coverage Δ | | |---|---|---| | [8.1](https://app.codecov.io/gh/open-telemetry/opentelemetry-php/pull/1406/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry) | `73.41% <100.00%> (+0.01%)` | :arrow_up: | | [8.2](https://app.codecov.io/gh/open-telemetry/opentelemetry-php/pull/1406/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry) | `73.73% <100.00%> (+0.11%)` | :arrow_up: | | [8.3](https://app.codecov.io/gh/open-telemetry/opentelemetry-php/pull/1406/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry) | `73.63% <100.00%> (ø)` | | | [8.4](https://app.codecov.io/gh/open-telemetry/opentelemetry-php/pull/1406/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry) | `73.65% <100.00%> (+0.02%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry#carryforward-flags-in-the-pull-request-comment) to find out more. | [Files with missing lines](https://app.codecov.io/gh/open-telemetry/opentelemetry-php/pull/1406?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry) | Coverage Δ | | |---|---|---| | [src/Contrib/Zipkin/SpanConverter.php](https://app.codecov.io/gh/open-telemetry/opentelemetry-php/pull/1406?src=pr&el=tree&filepath=src%2FContrib%2FZipkin%2FSpanConverter.php&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry#diff-c3JjL0NvbnRyaWIvWmlwa2luL1NwYW5Db252ZXJ0ZXIucGhw) | `97.16% <100.00%> (+0.70%)` | :arrow_up: | ... and [2 files with indirect coverage changes](https://app.codecov.io/gh/open-telemetry/opentelemetry-php/pull/1406/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry) ------ [Continue to review full report in Codecov by Sentry](https://app.codecov.io/gh/open-telemetry/opentelemetry-php/pull/1406?dropdown=coverage&src=pr&el=continue&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry). > **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry) > `Δ = absolute (impact)`, `ø = not affected`, `? = missing data` > Powered by [Codecov](https://app.codecov.io/gh/open-telemetry/opentelemetry-php/pull/1406?dropdown=coverage&src=pr&el=footer&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry). Last update [2c1da9a...f6030dd](https://app.codecov.io/gh/open-telemetry/opentelemetry-php/pull/1406?dropdown=coverage&src=pr&el=lastupdated&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry).