Pkg doesn't account for env variables in EDITOR

[Andarist]

node-external-editor/src/index.ts

Lines 141 to 142 in e1070a8

	const editorOpts = ExternalEditor.splitStringBySpace(editor).map((piece: string) => piece.replace("\\ ", " "));
	const bin = editorOpts.shift();

This doesn't account for env variables in the EDITOR variable and people might keep smth like this there:

NVIM_TUI_ENABLE_COLOR=1 nvim

which leads to an attempt to spawn NVIM_TUI_ENABLE_COLOR=1 here:

node-external-editor/src/index.ts

Lines 191 to 192 in e1070a8

	const editorProcess = spawnSync(
	this.editor.bin,

which is, obviously, not correct 😉

I'm not suuuuper sure if it's valid to keep env vars in EDITOR like this but according to my testing at least git handles this OK.

This got initially reported here:
changesets/changesets#498