Creating a release in GitHub requires passing boolean values

[hnrkndrssn]

In github-tag-release.json we pass the string value of the checkboxes for draft and prerelease settings, this used to work but failed this morning when doing a release.

Fix is to use [bool]::Parse for the draft and prerelease values and pass that to the GitHub API.

[hnrkndrssn]

Fixed in 2e9241b