zip: use []byte instead of string to prevent allocs

[gabriel-vasile]

goos: linux
goarch: amd64
pkg: github.com/gabriel-vasile/mimetype
cpu: Intel(R) Core(TM) i7-10510U CPU @ 1.80GHz
               │   master    │                 dev                  │
               │   sec/op    │    sec/op     vs base                │
Common/.xlsx-8   482.0n ± 4%   446.7n ±  3%   -7.33% (p=0.000 n=10)
Common/.pptx-8   1.999µ ± 3%   1.542µ ±  3%  -22.89% (p=0.000 n=10)
Common/.docx-8   1.501µ ± 2%   1.139µ ±  3%  -24.13% (p=0.000 n=10)
Common/.tar-8    1.134µ ± 3%   1.127µ ±  2%        ~ (p=0.670 n=10)
Common/.zip-8    882.4n ± 1%   778.6n ±  4%  -11.75% (p=0.000 n=10)
Common/.pdf-8    363.9n ± 2%   352.9n ±  2%   -3.02% (p=0.005 n=10)
Common/.jpg-8    508.9n ± 4%   504.3n ±  2%        ~ (p=0.190 n=10)
Common/.png-8    497.1n ± 3%   495.2n ±  2%        ~ (p=0.971 n=10)
Common/.gif-8    594.9n ± 5%   591.8n ±  2%        ~ (p=0.481 n=10)
Common/.xls-8    602.7n ± 4%   598.2n ± 11%        ~ (p=0.436 n=10)
Common/.webm-8   1.541µ ± 3%   1.549µ ±  3%        ~ (p=0.645 n=10)
Common/.csv-8    10.89µ ± 1%   10.96µ ±  1%        ~ (p=0.225 n=10)
geomean          981.7n        919.3n         -6.36%

               │    master    │                  dev                   │
               │     B/op     │     B/op      vs base                  │
Common/.xlsx-8     312.0 ± 0%     288.0 ± 0%   -7.69% (p=0.000 n=10)
Common/.pptx-8     592.0 ± 0%     288.0 ± 0%  -51.35% (p=0.000 n=10)
Common/.docx-8     504.0 ± 0%     288.0 ± 0%  -42.86% (p=0.000 n=10)
Common/.tar-8      200.0 ± 0%     200.0 ± 0%        ~ (p=1.000 n=10) ¹
Common/.zip-8      224.0 ± 0%     192.0 ± 0%  -14.29% (p=0.000 n=10)
Common/.pdf-8      192.0 ± 0%     192.0 ± 0%        ~ (p=1.000 n=10) ¹
Common/.jpg-8      192.0 ± 0%     192.0 ± 0%        ~ (p=1.000 n=10) ¹
Common/.png-8      192.0 ± 0%     192.0 ± 0%        ~ (p=1.000 n=10) ¹
Common/.gif-8      192.0 ± 0%     192.0 ± 0%        ~ (p=1.000 n=10) ¹
Common/.xls-8      288.0 ± 0%     288.0 ± 0%        ~ (p=1.000 n=10) ¹
Common/.webm-8     192.0 ± 0%     192.0 ± 0%        ~ (p=1.000 n=10) ¹
Common/.csv-8    7.331Ki ± 0%   7.332Ki ± 0%        ~ (p=0.179 n=10)
geomean            339.6          299.3       -11.85%
¹ all samples are equal

               │   master    │                 dev                  │
               │  allocs/op  │ allocs/op   vs base                  │
Common/.xlsx-8    4.000 ± 0%   3.000 ± 0%  -25.00% (p=0.000 n=10)
Common/.pptx-8   15.000 ± 0%   3.000 ± 0%  -80.00% (p=0.000 n=10)
Common/.docx-8   13.000 ± 0%   3.000 ± 0%  -76.92% (p=0.000 n=10)
Common/.tar-8     3.000 ± 0%   3.000 ± 0%        ~ (p=1.000 n=10) ¹
Common/.zip-8     6.000 ± 0%   2.000 ± 0%  -66.67% (p=0.000 n=10)
Common/.pdf-8     2.000 ± 0%   2.000 ± 0%        ~ (p=1.000 n=10) ¹
Common/.jpg-8     2.000 ± 0%   2.000 ± 0%        ~ (p=1.000 n=10) ¹
Common/.png-8     2.000 ± 0%   2.000 ± 0%        ~ (p=1.000 n=10) ¹
Common/.gif-8     2.000 ± 0%   2.000 ± 0%        ~ (p=1.000 n=10) ¹
Common/.xls-8     3.000 ± 0%   3.000 ± 0%        ~ (p=1.000 n=10) ¹
Common/.webm-8    2.000 ± 0%   2.000 ± 0%        ~ (p=1.000 n=10) ¹
Common/.csv-8     33.00 ± 0%   33.00 ± 0%        ~ (p=1.000 n=10) ¹
geomean           4.339        2.991       -31.05%
¹ all samples are equal