Pin workflow action refs to commit SHAs

[kitsuyui]

Summary

• Pin checkout, Rust toolchain, and Rust cache actions in test and binary release workflows to commit SHAs.
• Match the existing pinned action comments used by the other workflows.
• Keep workflow behavior unchanged while removing mutable action tag refs.

Changed files

• .github/workflows/test.yml
• .github/workflows/binary-release.yml

Verification

• go run github.com/rhysd/actionlint/cmd/actionlint@latest -shellcheck= .github/workflows/test.yml .github/workflows/binary-release.yml
• cargo fmt --all -- --check
• cargo check
• cargo test
• cargo clippy -- -D warnings
• cargo build
• git diff --check

[github-actions]

Code Metrics Report

	main (0a31f22)	#834 (577b774)	+/-
Coverage	69.3%	69.3%	0.0%
Code to Test Ratio	1:0.0	1:0.0	0.0
Test Execution Time	10s	12s	+2s

Details

  |                     | main (0a31f22) | #834 (577b774) | +/-  |
  |---------------------|----------------|----------------|------|
  | Coverage            |          69.3% |          69.3% | 0.0% |
  |   Files             |             18 |             18 |    0 |
  |   Lines             |           1816 |           1816 |    0 |
  |   Covered           |           1260 |           1260 |    0 |
  | Code to Test Ratio  |          1:0.0 |          1:0.0 |  0.0 |
  |   Code              |           2375 |           2375 |    0 |
  |   Test              |              0 |              0 |    0 |
- | Test Execution Time |            10s |            12s |  +2s |

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Reported by octocov