feat(get): add --print flag to output local repository path

[KeitaShimura]

feat(get): add --print flag to output local repository path

Related to #352

Summary

Add --print flag to ghq get that prints the cloned repository's local path to stdout.

# Clone and cd in one command
cd "$(ghq get --print x-motemen/ghq)"

# Works with bulk and --parallel too
ghq get --print --parallel repo1 repo2

Previously, --look was the only way to move into a cloned directory, but it spawns a subshell and cannot be used with command substitution $(). --print makes ghq get composable with other shell commands.

Changes

• Add --print flag to ghq get
• Print FullPath to stdout after each clone/update, in both sequential and parallel modes