remove rust-version from fuzz

[oech3]

No actual benefit to pin rust-version of non-production crate.

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/cut/bounded-memory (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/tail/inotify-dir-recreate (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/tail/symlink (passes in this run but fails in the 'main' branch)
Note: The gnu test tests/cp/link-heap is now being skipped but was previously passing.
Congrats! The gnu test tests/rm/many-dir-entries-vs-OOM is now passing!
Note: The gnu test tests/misc/write-errors was skipped on 'main' but is now failing.
Skip an intermittent issue tests/pr/bounded-memory (was skipped on 'main', now failing)

[codspeed-hq]

Merging this PR will improve performance by 3.39%

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 4 improved benchmarks
✅ 353 untouched benchmarks
⏩ 50 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Simulation	du_summarize_balanced_tree[(5, 4, 10)]	16.8 ms	16.1 ms	+4.11%
⚡	Simulation	cksum_sysv	68.4 ms	66.2 ms	+3.32%
⚡	Simulation	cksum_crc32b	39.7 ms	38.5 ms	+3.11%
⚡	Simulation	cksum_multiple_files	61.5 ms	59.7 ms	+3.01%

Tip

Curious why this is faster? Comment @codspeedbot explain why this is faster on this PR, or directly use the CodSpeed MCP with your agent.

---

_{Comparing oech3:fuzz-rust-ver (bff6c65) with main (92cbd2f)}

Footnotes

1. 50 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[xtqqczze]

Specifying rust-version doesn't pin the Rust toolchain to that version, so I don't see a benefit in removing it.

[xtqqczze]

⁠uufuzz is published to crates.io, so removing rust-version would remove this information from the package metadata.