update README to Makefile instructions

[sentilesdal]

We were still prescribing to use npm scripts, but most look like they were removed from package.json so I updated to the Makefile ones.

[github-actions]

Hyperdrive Gas Benchmark

Benchmark suite	Current: f3456da	Previous: 53bce0d	Deviation	Status
addLiquidity: min	1546 gas	1546 gas	0%	🟰
addLiquidity: avg	66578 gas	68099 gas	-2.2335%	✅
addLiquidity: max	292728 gas	292728 gas	0%	🟰
checkpoint: min	1150 gas	1150 gas	0%	🟰
checkpoint: avg	48047 gas	48288 gas	-0.4991%	✅
checkpoint: max	191173 gas	191173 gas	0%	🟰
closeLong: min	1492 gas	1492 gas	0%	🟰
closeLong: avg	28490 gas	28378 gas	0.3947%	🚨
closeLong: max	148543 gas	151400 gas	-1.8871%	✅
closeShort: min	1494 gas	1494 gas	0%	🟰
closeShort: avg	30192 gas	30237 gas	-0.1488%	✅
closeShort: max	129747 gas	129747 gas	0%	🟰
initialize: min	1495 gas	1495 gas	0%	🟰
initialize: avg	213307 gas	213307 gas	0%	🟰
initialize: max	253585 gas	253585 gas	0%	🟰
openLong: min	1432 gas	1432 gas	0%	🟰
openLong: avg	50749 gas	50733 gas	0.0315%	🚨
openLong: max	187405 gas	187405 gas	0%	🟰
openShort: min	1520 gas	1520 gas	0%	🟰
openShort: avg	49950 gas	49993 gas	-0.0860%	✅
openShort: max	180144 gas	180144 gas	0%	🟰
redeemWithdrawalShares: min	1488 gas	1488 gas	0%	🟰
redeemWithdrawalShares: avg	20050 gas	19937 gas	0.5668%	🚨
redeemWithdrawalShares: max	108516 gas	108516 gas	0%	🟰
removeLiquidity: min	1552 gas	1552 gas	0%	🟰
removeLiquidity: avg	150035 gas	150291 gas	-0.1703%	✅
removeLiquidity: max	324881 gas	324881 gas	0%	🟰

This comment was automatically generated by workflow using github-action-benchmark.

[jalextowle]

LGTM once the lint section is up to date.