Allow buffer polyfill v5 or v6

[mischnic]

Closes #8953

A dependency of buffer v6 now doesn't print the warning Could not find module "buffer" satisfying ^5.5.0. anymore (the only breaking change was dropped IE11 and Safari 9/10 compatibility)

Autoinstall now results in this (and installs version 6):

{
	"devDependencies": {
		"buffer": "^5.5.0||^6.0.0"
	}
}

[parcel-benchmark]

Benchmark Results

Kitchen Sink ✅

Timings

Description	Time	Difference
Cold	1.47s	+18.00ms
Cached	333.00ms	+6.00ms

Cold Bundles

No bundle changes detected.

Cached Bundles

No bundle changes detected.

React HackerNews ✅

Timings

Description	Time	Difference
Cold	6.98s	-59.00ms
Cached	417.00ms	-3.00ms

Cold Bundles

Bundle	Size	Difference	Time	Difference
dist/logo.8dd07848.png	244.00b	+0.00b	313.00ms	-48.00ms 🚀

Cached Bundles

No bundle changes detected.

AtlasKit Editor ✅

Timings

Description	Time	Difference
Cold	1.05m	+461.00ms
Cached	2.03s	+29.00ms

Cold Bundles

Bundle	Size	Difference	Time	Difference
dist/media-viewer.84e91773.js	541.95kb	+0.00b	7.45s	-2.69s 🚀
dist/EmojiPickerComponent.11881429.js	196.52kb	+0.00b	9.07s	-1.08s 🚀
dist/component-lazy.fbe36021.js	60.43kb	+0.00b	5.00s	-394.00ms 🚀
dist/codeViewerRenderer.915ef6b3.js	2.84kb	+0.00b	7.45s	-2.73s 🚀
dist/ro.a6eff34a.js	612.00b	+0.00b	5.57s	-1.69s 🚀

Cached Bundles

Bundle	Size	Difference	Time	Difference
dist/media-viewer.84e91773.js	541.95kb	+0.00b	7.42s	-1.08s 🚀
dist/EmojiPickerComponent.11881429.js	196.52kb	+0.00b	10.10s	+515.00ms ⚠️

Three.js ✅

Timings

Description	Time	Difference
Cold	4.98s	+14.00ms
Cached	271.00ms	+5.00ms

Cold Bundles

No bundle changes detected.

Cached Bundles

No bundle changes detected.

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