Updating github workflow file to use nuget-acceptable version numbers for packaging

[Banashek]

Fixes 513 and should unblock builds.

This change alters the versioning used by github actions for builds by utilizing the Github Run Identifier as an "Additional Label" (in semver parlance) rather than a major version number.

Example (from this failed build)

• Before: 2564178360 (System.ArgumentException: PackageVersion string specified '2564178360' is invalid.)
• After: 6.0.0-build.2564178360

This matches the semver logic: Example: 1.0.0-alpha < 1.0.0-alpha.1 < 1.0.0-alpha.beta < 1.0.0-beta < 1.0.0-beta.2 < 1.0.0-beta.11 < 1.0.0-rc.1 < 1.0.0. (ref: https://semver.org/)

[dustinmoris]

Thanks for that! I am extremely annoyed that .NET keeps changing shit like this all the time. This was fine in previous .NET Core versions and now they don't accept non-SemVer compatible versions anymore which is why this war broken. Appreciate the fix!