Support X.YYYZZZ version numbers as being a variant of semver for Perl projects

[tobyink]

Dotted decimal version numbers like v1.2.3 are rarely used by Perl projects. (Though some do.)

However, Perl has a convention that the number 1.002003 and the version v1.2.3 are equivalent.

So it would be nice if Perl libraries with exactly 6 decimal places would be shown as having a semantic version number. Similarly, any such version number > 1.000000 should be treated as 1.0.0 or greater.