fix: enhance quote to handle empty args

[antongolub]

closes #999
closes #1112

const _$ = $({ prefix: '', postfix: '' })
const p1 = _$`echo ${['-n', 'foo']}`
assert.equal(p1.cmd, 'echo -n foo')
assert.equal((await p1).toString(), 'foo')

const p2 = _$`echo ${[1, '', '*', '2']}`
assert.equal(p2.cmd, `echo 1 $'' $'*' 2`)
assert.equal((await p2).toString(), `1  * 2\n`)

• Tests pass
• Appropriate changes to README are included in PR