`vercel dev` still results to release build of rust

[Zxilly]

Seems the debug build only be enabled if VERCEL_BUILDER_DEBUG was set. But I think vercel cli won't set this. We need other way to know which mode we are running.

rust/src/index.ts

Line 36 in 954bdba

const BUILDER_DEBUG = Boolean(process.env.VERCEL_BUILDER_DEBUG ?? false);

rust/src/index.ts

Lines 71 to 81 in 954bdba

	await execa(
	'cargo',
	['build', '--bin', binaryName].concat(
	BUILDER_DEBUG ? ['--verbose'] : ['--quiet', '--release'],
	),
	{
	cwd: workPath,
	env: rustEnv,
	stdio: 'inherit',
	},
	);

Set this env manully won't be good idea as it produces lot of unnecessary log.

[ecklf]

Shipped in 4.0.8