Common toys imports

The subdirectories under this directory provide common toys tools and libraries used across multiple Google Cloud SDK Ruby language repositories.

Specifically:

• /toys/gapic provides a common set of tools used by GAPIC libraries, including builds, various test types, and CI.
• /toys/release provides the Ruby release system, including tools for controlling release-please, performing Rubygems releases, and building and publishing reference documentation.
• /toys/yoshi provides a set of utility classes for performing common steps such as interacting with GitHub and opening pull requests.

These resources can be invoked using the load_git directive. For example, GAPIC libraries can bring in toys/gapic using

load_git remote: "https://github.com/googleapis/ruby-common-tools.git",
         path: "toys/gapic",