Add support for build-time extra_hosts for Version 3

[kinnalru]

It work well for Version 2.3 since #5361 but invalid for Version 3

[shin-]

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[nlapshin]

Hello. Does this feature work in 3.x version?

I use docker-compose version 3.7 and the extra host doesn't work at the build stage.

[burka]

For anyone searching like me: It's solved in Version 3.9 docker/cli#2517 - you can add extra_hosts: in build: now.

[burka]

For anyone searching like me: It's solved in Version 3.9 docker/cli#2517 - you can add extra_hosts: in build: now.