Allow installing any supported version of Simulator

[dotdoom]

Right now the versions are restricted to those already preinstalled in the OS image.

Let's try to expand this a little, see this comment:

actions/runner-images#551 (comment)

[dotdoom]

And if anyone else ends up picking up this issue, here is another thought: the hack described in the comment should only be used if a version requirement specified by the Action user is unsatisfiable within the range of already installed simulators. Installing an extra version is not free, it performs I/O and takes CPU time.

We should also make sure it still works on hosted action runners, or make a disclaimer that it may not.

[dniHze]

As an option, this can be done pretty easily via xcodes, given it doesn't even need auth tokens to download platforms (for now). However, the I/O side might be potentially neglected with actions/tool-cache, but the cache archive size will be massive, so it might hit rate limits pretty quickly.