v2.1.3

Now Build is not compared.

SemVer("1.0.0+build") == SemVer("1.0.0+newbuild")
SemVer("1.0.0+build") == SemVer("1.0.0")
SemVer("1.0.0+build") > SemVer("1.0.0-rc.1")