Lighthouse-ci: Add SPA support to fallback server

[lili21]

the fallback-server does not support front-end router right now.

[patrickhulce]

Thanks for filing @lili21, good idea!

This should be fairly straightforward if anyone is looking for their first contribution :)

Basically add

app.get('*', (_, res) => res.sendFile(path.join(pathToBuildDir, 'index.html')))

to
https://github.com/GoogleChrome/lighthouse-ci/blob/3a34a7b0a9f57b78ec1d5c1be5263262408c61fa/packages/cli/src/collect/fallback-server.js#L18-L24

and a test to go along with it

[Amagon96]

Working on it! n.n/

[rdlabo]

I found this Issue after making pull request: https://github.com/GoogleChrome/lighthouse-ci/pull/159

@Amagon96 How is the progress? If you haven't started yet, I'd be happy to get feedback on this code.

Thanks.

[Amagon96]

Hi @rdlabo I think that is ok with your changes since it solves this issue, however I've check your changes and leave you a comment there, and you should use the closes #issueNumber, check it out ;)