Bump hammer, credo, dialyxir, ex_doc, benchee to latest compatible versions

[epinault]

Summary

Routine dependency update. No majors were held — every outdated package resolved to its latest release within the constraint already declared in mix.exs (all ~> ranges), so nothing needed a constraint edit.

Baseline (before any change) was green: mix compile --warnings-as-errors + mix test passed at 64d6cb9. No security advisories or retired packages (mix hex.audit); this repo doesn't have mix_audit installed so advisory scanning relied on mix hex.audit plus changelog reading.

Package-by-package

hammer 7.1.0 -> 7.5.0 (runtime dependency, own commit)

• Reviewed the CHANGELOG for every version in between (7.2.0-7.5.0).
• Changes: CAS-based race fixes in the Atomic backend, a renamed :algorithm -> :algorithm_module option in the Atomic backend, timestamp fixes in the ETS TokenBucket/LeakyBucket, a new :fix_window_per_key algorithm for ETS/Atomic, and a new mix hammer.install Igniter task.
• None of that touches the Mnesia backend this repo implements (Hammer.Mnesia, Hammer.Mnesia.{FixWindow,LeakyBucket,TokenBucket}) — no source changes needed.
• Note for awareness, not a blocker: hammer's CHANGELOG says 7.2.0 "dropped Elixir 1.14 support," but hammer's own mix.exs still declares elixir: "~> 1.14", so Hex resolution isn't affected. This repo's CI matrix (.github/workflows/ci.yml) still tests against Elixir 1.14/1.15/1.16, which I can't reproduce here (only 1.20.4 is available in this environment) — worth watching if that matrix job goes red.

Dev/test/bench tooling (batched, one commit)

• credo 1.7.13 -> 1.7.19, dialyxir 1.4.6 -> 1.4.7, ex_doc 0.39.1 -> 0.40.4, benchee 1.5.0 -> 1.5.1
• Transitive refresh pulled along: deep_merge 1.0.0 -> 1.0.2, earmark_parser 1.4.44 -> 1.4.46, erlex 0.2.7 -> 0.2.9, jason 1.4.4 -> 1.4.5, makeup 1.2.1 -> 1.2.2, makeup_erlang 1.0.2 -> 1.1.0, statistex 1.1.0 -> 1.1.1
• All dev/test/bench-only, no runtime impact.
• Side note: credo 1.7.13 has a false-positive on this repo as-is (mix credo --strict reports "Modules should have a @moduledoc tag" on all 4 lib modules, which already have moduledocs). credo 1.7.19 fixes it — mix credo --strict goes from 4 findings to 0 with no source changes.

Verification

This repo has no mix precommit alias, so I used its own CI steps (.github/workflows/ci.yml) as the equivalent gate, run after each batch and again on the final branch state:

• mix deps.unlock --check-unused
• mix compile --warnings-as-errors
• mix credo --strict --format=oneline
• mix test --warnings-as-errors --cover --include slow (27 tests, 89.6% coverage, above the 85% threshold)
• mix format --check-formatted
• mix dialyzer (0 errors, run once after the tooling batch since dialyxir moved)

Not run: the full CI version matrix (Elixir 1.14-1.18 / OTP 25-27) — only Elixir 1.20.4/OTP 29 is available in this environment.

Test plan

• CI green on this PR, including the version matrix (1.14 in particular, given the hammer note above)