Downgrade execa to 2.0.0 (which supports Node.js 8.0.0)

[jennifer-shehane]

• Closes Error when installing cypress using Node.js version < 8.12.0 #6512

User facing changelog

• We fixed an issue where Cypress would not install using Node.js 8 due to a dependency's engine restricting Node.js version to at least 8.12.0.
• Downgraded execa from 3.0.0 to 2.0.0.

Additional details

• execa 2.0.0 engines allows Node.js 8.0.0
• Opened issue for us to test Cypress against Node.js 8.0.0 specifically Test against Node.js 8.0.0 cypress-test-node-versions#47

How has the user experience changed?

Should no longer see the errors below during install:

yarn

error execa@3.3.0: The engine "node" is incompatible with this module. Expected version "^8.12.0 || >=9.7.0". Got "8.0.0"
error Found incompatible module.

npm install

> cypress@4.0.2 postinstall /Users/jennifer/Dev/cypress-transform-test/node_modules/cypress
> node index.js --exec install

/Users/jennifer/Dev/cypress-transform-test/node_modules/execa/index.js:18
	const env = extendEnv ? {...process.env, ...envOption} : envOption;
	                         ^^^

SyntaxError: Unexpected token ...
    at createScript (vm.js:74:10)
    at Object.runInThisContext (vm.js:116:10)
    at Module._compile (module.js:533:28)
    at Object.Module._extensions..js (module.js:580:10)
    at Module.load (module.js:503:32)
    at tryModuleLoad (module.js:466:12)
    at Function.Module._load (module.js:458:3)
    at Module.require (module.js:513:17)
    at require (internal/module.js:11:18)
    at Object.<anonymous> (/Users/jennifer/Dev/cypress-transform-test/node_modules/cypress/lib/util.js:18:13)

[cypress-bot]

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PR Review Checklist

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User Experience

• The feature/bugfix is self-documenting from within the product.
• The change provides the end user with a way to fix their problem (no dead ends).

Functionality

• The code works and performs its intended function with the correct logic.
• Performance has been factored in (for example, the code cleans up after itself to not cause memory leaks).
• The code guards against edge cases and invalid input and has tests to cover it.

Maintainability

• The code is readable (too many nested 'if's are a bad sign).
• Names used for variables, methods, etc, clearly describe their function.
• The code is easy to understood and there are relevant comments explaining.
• New algorithms are documented in the code with link(s) to external docs (flowcharts, w3c, chrome, firefox).
• There are comments containing link(s) to the addressed issue (in tests and code).

Quality

• The change does not reimplement code.
• There's not a module from the ecosystem that should be used instead.
• There is no redundant or duplicate code.
• There are no irrelevant comments left in the code.
• Tests are testing the code’s intended functionality in the best way possible.

Internal

• The original issue has been tagged with a release in ZenHub.

[cypress]

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Test summary

3247 • 0 • 49 • 0

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Run details

Project	cypress
Status	Passed
Commit	288e7a9
Started	Feb 20, 2020 4:53 PM
Ended	Feb 20, 2020 4:59 PM
Duration	05:28 💡
OS	Linux Debian - 9.11
Browser	Firefox 70

View run in Cypress Dashboard ➡️

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[bahmutov]

If we really want to support Node 8.0.0 then let's add a test job in https://github.com/cypress-io/cypress-test-node-versions/blob/master/circle.yml (we can even use branch 4.1.0 there for now to test upcoming change) that installs Cypress on Node 8.0.0 - and we can quickly add cypress/base:8.0.0 Docker image for that

[jennifer-shehane]

@bahmutov Yes, Brian asked me to followup with having the test-node-versions support this. Right now I believe it pulls latest 8 version, which does currently work, it's lower versions of 8 that are busted. Issue here: cypress-io/cypress-test-node-versions#47