Added new install_sources command option

[ryo-otake-sonix]

Overview

We can download the sources of all pre-built pod libraries by running the install_sources command. However, there is no need to download all the sources if you only want the sources of a specific pod library. Therefore, I made it possible to download only the pod libraries that we need by designating the pod libraries with options.

What we have done

• We added -p, --designate-pods option to install_sources command.
  • How to execute: pod_builder install_sources --designate-pods PodA PodB ...
• Added a process to get the argument when designate_pods option is enabled.
• Added a process to skip cloning when the designate_pods option is enabled and a library is not designated.

[tcamin]

Hi! Thanks for the pull request. Instead of having the --designate-pods what about making that the default and add a --all to install all sources?

So that the commands becomes more similar to the build one.

Usage:

    $ pod_builder install_sources  [OPTIONS] <PODNAME...>

      Install source of prebuilt pods to be able to step into and debug prebuilt's code.

Options:
    -a, --all                             Install all available sources
    -s, --no-stdin                   Never request interaction with sdtin (e.g. in CI environment)

[ryo-otake-sonix]

@tcamin Thanks for the review! I've fixed it, could you please re-review!

[ryo-otake-sonix]

@tcamin Thanks for the review! I've fixed it, could you please re-review!