Classify 3XX http status code as InvalidArgument

[AllenLuUber]

• [x] Description and context for reviewers: one partner, one stranger Currently 3XX is marked as unknown and classified as server error. This impacts the server SLA calculation. This diff adds support to classify it as InvalidArgument, a type of client error.
• [x] Docs (package doc)
• [x] Entry in CHANGELOG.md

[codecov[bot]]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.02 :tada:

Comparison is base (2ccc9b9) 85.32% compared to head (d505289) 85.35%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## dev #2205 +/- ## ========================================== + Coverage 85.32% 85.35% +0.02% ========================================== Files 270 270 Lines 15473 15475 +2 ========================================== + Hits 13203 13208 +5 + Misses 1847 1846 -1 + Partials 423 421 -2 ``` | [Impacted Files](https://codecov.io/gh/yarpc/yarpc-go/pull/2205?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=yarpc) | Coverage Δ | | |---|---|---| | [transport/http/codes.go](https://codecov.io/gh/yarpc/yarpc-go/pull/2205?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=yarpc#diff-dHJhbnNwb3J0L2h0dHAvY29kZXMuZ28=) | `100.00% <100.00%> (ø)` | | ... and [2 files with indirect coverage changes](https://codecov.io/gh/yarpc/yarpc-go/pull/2205/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=yarpc) Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=yarpc). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=yarpc)

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