The ‘parse’ function violates the second rule of semver.org where any
version number parts MUST not contain leading zeros:

    A normal version number MUST take the form X.Y.Z where X, Y, and Z
    are non-negative integers, and MUST NOT contain leading zeroes. X is
    the major version, Y is the minor version, and Z is the patch
    version. Each element MUST increase numerically.For instance:

        1.9.0 -> 1.10.0 -> 1.11.0.

Signed-off-by: William McKIE <mckie.william@hotmail.co.uk>