💄 feat(middleware/logger): latency match gin-gonic/gin formatter

[sixcolors]

Description

TagLatency to match gin-gonic/gin defaultLogFormatter, specifically %13v instead of %7v.

With %7v:

| 4.834µs |
| 1.136834ms |
| 1.000066333s |

With %13v, like gin https://github.com/gin-gonic/gin/blob/62b50cfbc0de877207ff74c160a23dff6394f563/logger.go#L143:

|       4.333µs |
|    1.133916ms |
|  1.000057458s |

And, adds Test_Logger_WithLatency, which proves that the logger would show he smallest unit that makes sense. (except for ns, which is probably too fast for most systems to test).

Fixes #2561

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I tried to make my code as fast as possible with as few allocations as possible

Commit formatting:

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[gaby]

lgtm