Static files Cache-Control maxAge hardcode

[SinaniG1996]

Hi. I have encountered on issue that i cant change Cache-Control maxage value for static files (e. g. .ico, .png). It seems this is because in lib/app:75 maxAge value hardcoded for such files.
Could you please move Cache ttl to config.
Something like this:

pluginOptions: {
    ssr: {
      ...
      // See https://ssr.vuejs.org/guide/build-config.html#externals-caveats
      nodeExternalsWhitelist: [/\.css$/, /\?vue&type=style/],
      // Static files Cache-Control maxAge value
      staticCacheTtl: 1000 * 60 * 60 * 24 * 30, <---------------
      // Function to connect custom middlewares
      extendServer: app => {
        const cookieParser = require('cookie-parser')
        app.use(cookieParser())
      },
      ...
  }

[SinaniG1996]

create pull request #138