Enhance semver test suite

[toddbaert]

We need to add assertions to confirm support for evaluating incoming context values which are numeric (ie: 1, 1.2 as opposed to "1", "1.2" ).

Additionally, review the matrix of params/assertions in flagd-core for semver and compare that to our gherkin table and associated semver flag configurations to see if we're missing any significant classes of assertions.

Requirements:

• support for numeric context value comparisons against strings are asserted ("1.2" > 1.1 == true)
• review assertions to see if any additional classes of comparisons are not represented