chore: bump version to 5.0.1

Patch release — no public API changes.

Bug fixes

• Backoff delay overflow with very large Delay — the shift cap was computed via math.Log2 on a float64, which underflowed for delays near math.MaxInt64, producing invalid backoff delays. The cap is now derived exactly from the bit length of math.MaxInt64. (#161)
• AttemptsForError is now honored when Attempts is 0 (UntilSucceeded) — the per-error budget was previously ignored in the retry-until-success loop; this also fixes a uint underflow when a budget of 0 was configured, which caused infinite retries. (#163, fixes #137)
• Unbounded error accumulation with LastErrorOnly(true) — errors were appended to the internal error log on every attempt even though only the last one is returned, growing memory without bound on long retry runs (e.g. Attempts(math.MaxUint) + context cancellation). Only the last error is retained now; the returned error is unchanged. (#155, fixes #118)

Documentation & tooling

• Clarified the v5 migration for DoWithData → NewWithData[T] (#152)
• README is now generated by an in-repo stdlib tool (tools/genreadme) with a CI golden-file check, replacing the unmaintained godocdown — the v5 changelog and doc links now render correctly on both GitHub and pkg.go.dev (#169, resolves #77)
• CI: Go 1.26/1.27 added to the matrix, pre-1.24 Go excluded from macOS runners, Codecov no longer fails Dependabot PRs (#165, #166)
• Development dependency: testify 1.11.1 → 1.12.1 (#168)

Thanks to @bensynapse, @AdamMagued, @Yanhu007, @c-tonneslan, @AruneshDwivedi and @team-humaki — whose contributions, including the ones superseded during review, shaped this release. 🙏

What's Changed

• Use Makefile lint target instead of blocked GitHub Action by @JaSei in #143
• default type is combination of backoff and random by @JaSei in #144
• Enhance readme + coverage by @JaSei in #146
• default branch is main by @JaSei in #147
• Proposal for v5 API: retry.New(...).Do(func) by @msf in #148
• upgrade to v5.0.0 with Go 1.20 multiple error wrapping support by @JaSei in #149

New Contributors

• @msf made their first contribution in #148

Full Changelog: 4.7.0...v5.0.0