fix(v2): transpile libs with too recent syntax with babel

[slorber]

Motivation

Some libs (many from Sindre Sorhus) use too recent ES syntax and should be transpiled with Babel

copy-text-to-clipboard contains try {} catch {} for example

Not doing this means we have some older browsers (like Edge 18 released in nov 2018) not supported while it could easily.

Noticed this while testing browser support of Docusaurus in #4766

Have you read the Contributing Guidelines on pull requests?

yes

Test Plan

preview + inspecting JS output + testing on Edge 18

[netlify]

[V1]

Built with commit 0410466

https://deploy-preview-4789--docusaurus-1.netlify.app

[netlify]

[V2]

Built with commit 0410466

https://deploy-preview-4789--docusaurus-2.netlify.app

[github-actions]

⚡️ Lighthouse report for the changes in this PR:

Category	Score
🟠 Performance	88
🟢 Accessibility	96
🟢 Best practices	100
🟢 SEO	100
🟢 PWA	95

Lighthouse ran on https://deploy-preview-4789--docusaurus-2.netlify.app/

[github-actions]

Size Change: -31 B (0%)

Total Size: 660 kB

Filename	Size	Change
website/build/assets/js/main.********.js	483 kB	-31 B (0%)

ℹ️ View Unchanged

Filename	Size	Change
website/build/assets/css/styles.********.css	88.5 kB	0 B
website/build/blog/2017/12/14/introducing-docusaurus/index.html	62 kB	0 B
website/build/docs/introduction/index.html	235 B	0 B
website/build/index.html	26.9 kB	0 B

_{compressed-size-action}

[slorber]

works on Edge 18 now

[tony]

Unknown if this is related, but when updating from docusaurus 2.0.0-beta.0 to 2.0.0-beta.1, I get this with yarn build and yarn serve;

Uncaught (in promise) ReferenceError: exports is not defined

@echarles got a similar error in #5142

Not sure if this is related to my personal configuration, changes to webpack, this PR, or somewhere else. There's a lot of action going on

edit: Narrow it down from beta 0 -> beta 3 to beta 0 -> beta 1

[slorber]

@tony without repro I can't do anything

[tony]

@slorber no problem. If I narrow it down I'll make an issue