Default branch to stable instead of main during install

[athompson-a2]

Bug Report

• Yes, I reviewed the contribution guidelines.
• Yes, more specifically, I reviewed the guidelines on how to write clear bug reports.

Describe the current, buggy behavior

As discussed here: wp-cli/find-command#77 (comment)

The default behavior of wp package install is to install from the main branch. The default behavior should be to install from stable instead. As the repo is right now, an installation will fail without specifying stable. Please refer to the linked discussion for output.

Describe what you would expect as the correct outcome

No errors and a correctly installed package should occur without specifying a specific branch

Provide a possible solution

Default to stable instead of main

Provide additional context/Screenshots

wp-cli/find-command#77 (comment)