Add tests for pnpm and yarn (#117) #7

# to view logs

Run time

Learn about OS # on GitHub Actions

Job	Run time
test (ubuntu-latest, lts/*, npm)	11m 38s
test (ubuntu-latest, lts/*, pnpm)	12m 21s
test (ubuntu-latest, lts/*, yarn)	12m 9s
test (ubuntu-latest, 18, npm)	12m 17s
test (ubuntu-latest, 18, pnpm)	12m 27s
test (ubuntu-latest, 18, yarn)	11m 49s
test (windows-latest, lts/*, npm)	14m 39s
test (windows-latest, lts/*, pnpm)	14m 18s
test (windows-latest, lts/*, yarn)	14m 0s
test (windows-latest, 18, npm)	15m 46s
test (windows-latest, 18, pnpm)	14m 27s
test (windows-latest, 18, yarn)	13m 58s
test (macos-latest, lts/*, npm)	13m 51s
test (macos-latest, lts/*, pnpm)	13m 3s
test (macos-latest, lts/*, yarn)	12m 44s
test (macos-latest, 18, npm)	13m 24s
test (macos-latest, 18, pnpm)	14m 28s
test (macos-latest, 18, yarn)	12m 47s
automerge	0s
	4h 0m 6s