Bump pnpm/action-setup to v4 #868

Job	Run time
Lint JS	16s
Tests: Type Check	16s
Slow tests: defaults with npm	2m 5s
Slow tests: defaults with yarn	1m 32s
Tests (addon-location)	45s
Slow tests: typescript with npm	2m 8s
Slow tests: defaults with pnpm	51s
Tests (test-app-location)	49s
Slow tests: typescript with yarn	1m 37s
Tests (addon-only)	28s
Slow tests: typescript with pnpm	1m 15s
Tests (monorepo with npm)	1m 34s
Tests (monorepo with yarn)	1m 9s
Tests (monorepo with pnpm)	47s
Tests (rollup-build)	51s
Tests (declarations-configuration)	31s
	16m 54s

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