Add pre-release build option

[jtpalmer]

Description

Adds support for a pre-release build configuration option. The pre-release tag is used for versioning of alpha/beta/release candidate packages.

Comments have also been added to the OpenXdmod\Build\Config class.

Motivation and Context

Version/release numbers generated by our current process result in incorrectly versioned RPM packages. e.g.:

For the configuration:

• version: 5.6.0rc1
• release: 0.1

Results in:

• Tarball: xdmod-5.6.0rc1.tar.gz
• CentOS 6 RPM: xdmod-5.6.0rc1-0.1.el6.noarch.rpm (note that rc1 is before 0.1)

The proper CentOS 6 RPM name is: xdmod-5.6.0-0.1.rc1.el6.noarch.rpm (note that 0.1 is defore rc1)

Moving "rc1" into the "release" portion of the configuration would fix the RPM, but then it is not used as part of the tarball (since that is not intended to be used as part of the tarball name).

This is an issue because it breaks the RPM upgrade process. The release portion of the versions must be sortable.

The new process would use these values:

• version: 5.6.0
• release: 0.1
• prerelease: rc1

And gives the desired results:

• Tarball: xdmod-5.6.0rc1.tar.gz
• CentOS 6 RPM: xdmod-5.6.0-0.1.rc1.el6.noarch.rpm

Refer to:

• https://fedoraproject.org/wiki/Packaging:Versioning
• https://fedoraproject.org/wiki/Package_Versioning_Examples

Tests performed

Built packages with and without the pre-release configuration being used. Compared generated RPM spec files and the other contents of the tarballs.

Types of changes

• 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 as found in the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.