ci(github-actions): use julia-actions/cache #226

Job	Run time
downgrade	1h 33m 22s
test (1, ubuntu-latest, conv, default, true)	39m 37s
test (1, ubuntu-latest, dense, default, true)	46m 44s
test (1, ubuntu-latest, normalization, default, true)	1h 47m 5s
test (1, ubuntu-latest, misc, default, true)	48m 12s
test (1, ubuntu-latest, dense, default, false)	38m 46s
test (1, ubuntu-latest, misc, default, false)	44m 44s
test (1, macos-latest, all, default, true)	5h 48m 6s
test (1, windows-latest, all, default, true)	1h 56m 26s
	14h 43m 2s

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