remove lexical-core dependency

[Licenser]

closes #312

[github-actions]

Benchmark for c3a10c2

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Test	Base	PR	%
apache_builds/simd_json::to_tape_with_buffers	89.8±1.76µs	90.3±1.31µs	+0.56%
canada/simd_json::to_tape_with_buffers	3.8±0.13ms	3.7±0.13ms	-2.63%
citm_catalog/simd_json::to_tape_with_buffers	1098.7±72.60µs	1105.7±77.47µs	+0.64%
event_stacktrace_10kb/simd_json::to_tape_with_buffers	3.6±0.19µs	3.6±0.20µs	0.00%
github_events/simd_json::to_tape_with_buffers	39.4±0.96µs	39.7±0.85µs	+0.76%
log/simd_json::to_tape_with_buffers	1572.5±70.46ns	1540.0±71.20ns	-2.07%
twitter/simd_json::to_tape_with_buffers	434.7±25.10µs	436.1±25.32µs	+0.32%