Fix Wrong Header Support

sw.js

const buffer = await res.arrayBuffer()
if(urlStr.match(/\.html$/g) || urlStr.match(/\.htm$/g)){
    return new Response(buffer,{
        status: 200,
        headers: {
            'Content-Type': 'text/html;chartset=utf-8'
        }
    })
}else{
    return res
}