fix _ typo in `CARGO_ZIGBUILD_RUSTC_VERSION` #1120

Job	Run time
Check	19s
Clippy	21s
Rustfmt	6s
spellcheck	8s
Test Suite (ubuntu-latest, 1.74.0, 0.10.1)	11m 48s
Test Suite (ubuntu-latest, 1.74.0, 0.13.0)	10m 9s
Test Suite (ubuntu-latest, stable, 0.10.1)	12m 44s
Test Suite (ubuntu-latest, stable, 0.13.0)	10m 51s
Test Suite (ubuntu-latest, stable, master)	1m 26s
Test Suite (ubuntu-latest, nightly, 0.10.1)	13m 10s
Test Suite (ubuntu-latest, nightly, 0.13.0)	11m 3s
Test Suite (ubuntu-latest, nightly, master)	1m 35s
Test Suite (macos-13, 1.74.0, 0.10.1)	24m 41s
Test Suite (macos-13, 1.74.0, 0.13.0)	15m 30s
Test Suite (macos-13, stable, 0.10.1)	28m 42s
Test Suite (macos-13, stable, 0.13.0)	19m 41s
Test Suite (macos-13, stable, master)	3m 52s
Test Suite (macos-13, nightly, 0.10.1)	26m 16s
Test Suite (macos-13, nightly, 0.13.0)	21m 55s
Test Suite (macos-13, nightly, master)	5m 27s
Test Suite (windows-latest, 1.74.0, 0.10.1)	19m 45s
Test Suite (windows-latest, 1.74.0, 0.13.0)	16m 25s
Test Suite (windows-latest, stable, 0.10.1)	18m 41s
Test Suite (windows-latest, stable, 0.13.0)	17m 42s
Test Suite (windows-latest, stable, master)	5m 21s
Test Suite (windows-latest, nightly, 0.10.1)	19m 47s
Test Suite (windows-latest, nightly, 0.13.0)	16m 28s
Test Suite (windows-latest, nightly, master)	4m 40s
	5h 38m 33s

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