Optionalmajormajor version number.
Optionalminorminor version number.
Optionalpatchpatch version number.
Optionalprereleaseoptional prerelease version string.
an empty string implies that no pre-release version annotation exists.
Optionalbuildoptional version build information.
an empty string implies that no build-information annotation exists.
Optionaloperatorthe unary operator.
an interface for carrying optional operator information, along with wildcards (undefined fields).