fix: Don't write to tmpdir in CI #275

Job	Run time
Docs	19s
Test (macos-latest, stable)	1m 1s
Check MSRV (ubuntu-latest)	26s
rustfmt	15s
lockfile	20s
Minimal versions (ubuntu-latest)	28s
clippy	29s
Test (windows-latest, stable)	2m 18s
Coverage	31s
Test (ubuntu-latest, stable)	51s
CI	3s
	7m 1s

Provide feedback