WHEEL file: Mention scikit-build in Generator field

[jcfr]

Instead of

Wheel-Version: 1.0
Generator: bdist_wheel (0.29.0)
Root-Is-Purelib: false
Tag: cp27-cp27mu-linux_x86_64

we could have

Wheel-Version: 1.0
Generator: skbuild.command.bdist_wheel (0.3.0)
Root-Is-Purelib: false
Tag: cp27-cp27mu-linux_x86_64

In section file-contents, the PEP-0427 mentions the following:

[...]

8. Generator is the name and optionally the version of the software that produced the archive.

[...]

Implementation of bdist_wheel is in

https://bitbucket.org/pypa/wheel/src/54ddbcc9cec25e1f4d111a142b8bfaa163130a61/wheel/bdist_wheel.py?at=default&fileviewer=file-view-default#bdist_wheel.py-260:265

[...]

    def write_wheelfile(self, wheelfile_base, generator='bdist_wheel (' + wheel_version + ')'):
        from email.message import Message
        msg = Message()
        msg['Wheel-Version'] = '1.0'  # of the spec
        msg['Generator'] = generator
        msg['Root-Is-Purelib'] = str(self.root_is_pure).lower()
[...]

Otherwise, here is what other tools are doing:

• https://github.com/takluyver/flit/blob/master/flit/wheel.py#L21

[...]
wheel_file_template = """\
Wheel-Version: 1.0
Generator: flit {version}
Root-Is-Purelib: true
""".format(version=__version__)
[...]

• https://bitbucket.org/dholth/enscons/src/

???

• https://github.com/cournape/numscons

???