chore(ci): CI scripts cleanup, add Node 14 runs, bump checkout action

[Simek]

Motivation

This PR clean up the GitHub action workflow files and adds Node 14 run to the "Yarn v1 E2E" run and Node 15 to the "Yarn v2 E2E" run to ensure that not only the minimal version of Node, but also Active LTS and Current do no produce any errors for the users.

I have also bumped all the remaining actions/checkout@v1 to v2 - some of workflows were already using v2. Also the Node version declaration has been updated to the recommended syntax - https://github.com/actions/setup-node.

Additionally I have moved the Yarn version set command at the beginning of script so initial installation would also be performed using Yarn v2.

Have you read the Contributing Guidelines on pull requests?

Yes.

Test Plan

Need to run the CI.

Related PRs

No.

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Deploy preview for docusaurus-2 ready!

Built without sensitive environment variables with commit b32bf8e

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[github-actions]

⚡️ Lighthouse report for the changes in this PR:

Category	Score
🟠 Performance	88
🟢 Accessibility	99
🟢 Best practices	100
🟢 SEO	100
🟢 PWA	95

Lighthouse ran on https://deploy-preview-3849--docusaurus-2.netlify.app/classic/

[github-actions]

Size Change: +21 B (0%)

Total Size: 157 kB

ℹ️ View Unchanged

Filename	Size	Change
website/build/blog/2017/12/14/introducing-docusaurus/index.html	20.7 kB	0 B
website/build/docs/introduction/index.html	180 B	0 B
website/build/index.html	5.86 kB	0 B
website/build/main.********.js	113 kB	+21 B (0%)
website/build/styles.********.css	17.6 kB	0 B

_{compressed-size-action}

[Simek]

Changing Node from 15 to 14 resolved the Yarn v2 E2E workflow issue, it look like this PR brought to table two problems:

• Yarn v2 do not work with the Docusaurus workspace so contributors using it by default would struggle (but it will work for the users and might work for few, single packages) - it's also nice that you can switch between the Yarn versions that fast
• init do not work correctly on Node 15, which is shipped with NPM 7 by default, this might be due to:
  • changed npx implementation - https://blog.npmjs.org/post/626173315965468672/npm-v7-series-beta-release-and-semver-major
  • other NPM 7 changes

[slorber]

Thanks, seems to be fine for now, but we'll try to figure out these issues you reported