Enable prefixing tag with 'v'

[andybavier]

This PR updates the tag-github.yml workflow in the following ways:

• Adds a boolean flag for prefixing the version tag with 'v' (default: false). The convention for most of the onosproject repos is to add the 'v' to the semver in the VERSION file when tagging the release.
• Fixes a parameter issue when calling create-github-release-action
• Uses the GITHUB_TOKEN when creating the release, per best practices

Insights > Dependency graph > Dependents indicates that only two repos use this workflow at present. I will update them as needed once this PR merges.