Specify the minimum major and minor version

[adamralph]

E.g.

<MinVerMinimumMajorMinor>2.0</MinVerMinimumMajorMinor>

(and MINVER_MINIMUM_MAJOR_MINOR synonym for use in an env var)

If no tag is found with a higher version, the version is MAJOR.MINOR.0-alpha.0, similar to the logic for when no tag is found at all (0.0.0-alpha.0).

[adamralph]

Released in alpha 10.

[adamralph]

Closed in #71.

[adamralph]

Released in alpha 12.