Fix GitHub CI npm install by using --legacy-peer-deps

[nksazonov]

#676 introduces a GitHub Actions issue related to peer-deps:

npm ERR! code ERESOLVE
npm ERR! ERESOLVE could not resolve
npm ERR! 
npm ERR! While resolving: @nomiclabs/[email protected]
npm ERR! Found: @nomiclabs/[email protected]
npm ERR! node_modules/@nomiclabs/hardhat-ethers
npm ERR!   dev @nomiclabs/hardhat-ethers@"npm:hardhat-deploy-ethers@^0.3.0-beta.13" from the root project
npm ERR! 
npm ERR! Could not resolve dependency:
npm ERR! peer @nomiclabs/hardhat-ethers@"^2.0.0" from @nomiclabs/[email protected]
npm ERR! node_modules/@nomiclabs/hardhat-waffle
npm ERR!   dev @nomiclabs/hardhat-waffle@"^2.0.2" from the root project
npm ERR! 
npm ERR! Conflicting peer dependency: @nomiclabs/[email protected].[6](https://github.com/statechannels/go-nitro/runs/6967242499?check_suite_focus=true#step:4:7)
npm ERR! node_modules/@nomiclabs/hardhat-ethers
npm ERR!   peer @nomiclabs/hardhat-ethers@"^2.0.0" from @nomiclabs/[email protected]
npm ERR!   node_modules/@nomiclabs/hardhat-waffle
npm ERR!     dev @nomiclabs/hardhat-waffle@"^2.0.2" from the root project
npm ERR! 
npm ERR! Fix the upstream dependency conflict, or retry
npm ERR! this command with --force, or --legacy-peer-deps
npm ERR! to accept an incorrect (and potentially broken) dependency resolution.
npm ERR! 
npm ERR! See /home/runner/.npm/eresolve-report.txt for a full report.
npm ERR! A complete log of this run can be found in:
npm ERR!     /home/runner/.npm/_logs/2022-06-20T12_54_01_03[8](https://github.com/statechannels/go-nitro/runs/6967242499?check_suite_focus=true#step:4:9)Z-debug-0.log

This issue is caused by an npm-alias created for @nomiclabs/hardhat-ethers hiding hardhat-deploy-ethers.

As of time of creating this PR, there seems to be no general solution to this issue.

Thus, it was decided to bypass the problem by using --legacy-peer-deps flag (good post about it here).

Also npm ci is used instead of npm i to make a clean install of dependencies (copied from npm help ci):

In short, the main differences between using npm install and npm ci are:

  • The project must have an existing package-lock.json or npm-shrinkwrap.json.

  • If dependencies in the package lock do not match those in package.json, npm ci will exit with an error, instead of updating the package lock.

  • npm ci can only install entire projects at a time: individual dependencies cannot be added with this command.

  • If a node_modules is already present, it will be automatically removed before npm ci begins its install.

Nevertheless, --legacy-peer-deps is not a cure and an issue to fix peer-deps and return to pure npm ci is to be created.

[geoknee]

Thanks for the detailed write up!