This commit introduces a beforeWorkspacePacking
hook which converts `backstage:` versions back
into `npm:`` versions when packages are packed for
publish. This allows the `backstage:` protocol to
be used even for packages that are intended to
themselves be published (such as packages in
third-party Backstage plugin monorepos outside
core).
Signed-off-by: MT Lewis <mtlewis@users.noreply.github.com>