chore: remove clippy msrv

[DaniPopes]

Clippy MSRV is out of sync. It defaults to project Rust version so we can just remove the file.

[codspeed-hq]

Merging this PR will degrade performance by 45.99%

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 3 improved benchmarks
❌ 2 regressed benchmarks
✅ 381 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
⚡	most_significant_bits/4096/4096	28.9 µs	26.1 µs	+10.87%
❌	parse/decimal/384/max	5.2 ms	8.3 ms	-37.6%
❌	parse/decimal/384/zero	486 µs	899.8 µs	-45.99%
⚡	to/f32/4096	29.1 µs	26.3 µs	+10.97%
⚡	to/f64/4096	29.3 µs	26.3 µs	+11.17%

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_{Comparing DaniPopes:clippies2 (2e2e920) with main (a21eb25)}