refactor: use utf8 strings as mem cache keys

[KSXGitHub]

Initially, the use of OsString was to allow non-UTF8 paths. However, the index file feature requires serde which in turns require UTF-8 to serialize. So the need for OsString ceases to be necessary, and removing it open new opportunities for some micro-optimizations.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (6d8cec2) 92.68% compared to head (c2d89d3) 92.68%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #222   +/-   ##
=======================================
  Coverage   92.68%   92.68%           
=======================================
  Files          57       57           
  Lines        2871     2872    +1     
=======================================
+ Hits         2661     2662    +1     
  Misses        210      210           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[github-actions]

Micro-Benchmark Results

Linux

group                          main                                   pr
-----                          ----                                   --
tarball/download_dependency    1.01      6.7±0.28ms   650.0 KB/sec    1.00      6.6±0.21ms   654.7 KB/sec

[github-actions]

Integrated-Benchmark Report (Linux)

Scenario: Frozen Lockfile

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
pacquet@HEAD	127.2 ± 9.8	114.5	144.3	1.03 ± 0.11
pacquet@main	123.2 ± 9.8	107.5	137.7	1.00

BENCHMARK_REPORT.json

{
  "results": [
    {
      "command": "pacquet@HEAD",
      "mean": 0.1271716063466667,
      "stddev": 0.009812358487650672,
      "median": 0.12619836648,
      "user": 0.060102726666666675,
      "system": 0.2001150733333333,
      "min": 0.11450732448000002,
      "max": 0.14428669348,
      "times": [
        0.14428669348,
        0.11990778348000002,
        0.12619836648,
        0.13605476948,
        0.12718388648,
        0.11450732448000002,
        0.12066137548000001,
        0.13758830448,
        0.12542734648,
        0.12743158148,
        0.13692406248,
        0.11953791848000002,
        0.14075418748000001,
        0.11592374748000002,
        0.11518674748000002
      ],
      "exit_codes": [
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0
      ]
    },
    {
      "command": "pacquet@main",
      "mean": 0.12316214754666668,
      "stddev": 0.009758218348705645,
      "median": 0.12175780848000001,
      "user": 0.05872752666666667,
      "system": 0.20377233999999997,
      "min": 0.10750951548000001,
      "max": 0.13768289148,
      "times": [
        0.13554187048,
        0.11585921048000002,
        0.13768289148,
        0.11726989848000001,
        0.11095596748000001,
        0.11996457548000002,
        0.12027272148000001,
        0.13042775948,
        0.11030591948000001,
        0.13455231048,
        0.12728008348,
        0.12497080248000002,
        0.12175780848000001,
        0.13308087848,
        0.10750951548000001
      ],
      "exit_codes": [
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0,
        0
      ]
    }
  ]
}

[zkochan]

That's fine. Neither pnpm nor the other node.js based alternatives support non-utf8 chars.