feat(version): support custom command for git tag

[ghiscoding]

Description

As per Lerna PR 2760

Added support to override the executed command for git tag via CLI options and lerna.json entry.

Motivation and Context

As per Lerna PR

Some CD/CI systems have no direct write access to the repository and are not able to tag the normal way via git. An optional wrapper command/alias might be defined.

How Has This Been Tested?

• Added unit-tests
• ./core/lerna/cli.js version -h shows new option

Types of changes

• Chore (change that has absolutely no effect on users)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.