Install script should respect $XDG_CACHE_HOME env var on linux

[gasinvein]

According to XDG Base Directory specification, programs should look at $XDG_CACHE_HOME environment variable to determine the cache directory, and only if it's not set, fall back to the ~/.cache path.
Currently, the fallback path ~/.cache is hardcoded in install.ts:

esbuild/lib/install.ts

Lines 105 to 110 in c04240a

	function getCachePath(name: string): string {
	const home = os.homedir();
	const common = ['esbuild', 'bin', `${name}@${version}`];
	if (process.platform === 'darwin') return path.join(home, 'Library', 'Caches', ...common);
	if (process.platform === 'win32') return path.join(home, 'AppData', 'Local', 'Cache', ...common);
	return path.join(home, '.cache', ...common);