Fix for multiple DDEV hostnames

[bserem]

Addresses #18

This is heavily inspired (as in "copied") from https://github.com/tyler36/ddev-cypress/pull/54/files

I was facing the same issues on projects with multiple hostnames, where surprisingly even the main domain (my.ddev.site) was not resolving for backstop.
The PR is fixing things for me.

[bserem]

@mmunz this has been working for me, any thoughts? Shall we merge it?

[mmunz]

@bserem the code in

ddev-backstopjs/backstopBuild/entrypoint.sh

Line 7 in 7605ba4

if [ -n "$routerIp" ]; then

didn't work for you? This should already add the hostnames and also works for me with additional_hostnames. I didn't try with additional_fqdns though.

[bserem]

@mmunz , it only works for me if I apply the changes of this merge request when I use multiple hostnames in DDEV.

So, for all projects I rely on your repo, but for projects with multiple hostnames I still rely on https://github.com/bserem/ddev-backstopjs/tree/multiple-hostnames
I do not use additional FQDNs myself, so I can't test those yet.

[stasadev]

This fix will not be needed in the next DDEV release (v1.24.9):

• feat(docker): auto HTTP/S communication via network aliases instead of external_links ddev/ddev#7642

Make sure to add ddev_version_constraint: '>= v1.24.9' to install.yaml when it's out.