experiment: add cross workspace cache #144

Job	Run time
rustfmt	16s
stale-label	19s
clippy	1m 51s
schema	33s
lint-docs	1m 59s
build_std	3m 43s
Tests Linux x86_64 stable	6m 14s
test_gitoxide	9m 6s
resolver	3m 4s
docs	3m 9s
Tests Linux aarch64 stable	5m 58s
Tests Linux x86_64 beta	6m 15s
Tests macOS aarch64 stable	5m 56s
Tests Linux aarch64 nightly	6m 12s
msrv	2m 38s
Tests Windows x86_64 MSVC nightly	6m 14s
Tests Windows x86_64 gnu nightly	6m 14s
Tests Windows aarch64 MSVC stable	6m 9s
lockfile	15s
Tests Windows aarch64 MSVC nightly	6m 8s
Tests macOS aarch64 nightly	6m 1s
Tests Windows x86_64 MSVC stable	6m 14s
Tests Linux x86_64 nightly	6m 16s
check-version-bump	-1s
conclusion	2s
	1h 40m 45s

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