Run matrix builds sequentially in the same container

[ericoporto]

Description

I have some cases where I need to build for debug/release or have different build types using CMake, and in all of these I could decently build sequentially in the same container, since it would be using new directories and everything, and saving me from waiting the container to startup.

Unfortunately as far as I can tell matrix always makes me build things in different containers in parallel.

Context

Looking into how to reduce compute credits usage. Also, there is a lot of delay into getting the Windows machines to start (actually they are mostly not even starting in my pipeline), this would make them run faster.

Anything Else

There is a chance there is already a way to do this using yaml hackery or the other complex language, but I just wanted a sequentially: true.