Branches with uppercase confuse the version extraction from merge commit

[anobleperson]

Branches with uppercase confuse the version extraction from merge commit. If the release branch has upper case prefix, the version number cannot be extracted.

This test passes:
[Test]
public void CanHandleReleaseBranchWithStability()
{
using (var fixture = new EmptyRepositoryFixture(new Config()))
{
fixture.Repository.MakeATaggedCommit("1.0.3");
fixture.Repository.CreateBranch("develop");
fixture.Repository.MakeCommits(5);
fixture.Repository.CreateBranch("release-2.0.0-Final");
fixture.Repository.Checkout("release-2.0.0-Final");

        fixture.AssertFullSemver("2.0.0-beta.1+5");
    }
}

This test fails:
[Test]
public void CanHandleReleaseBranchWithStability()
{
using (var fixture = new EmptyRepositoryFixture(new Config()))
{
fixture.Repository.MakeATaggedCommit("1.0.3");
fixture.Repository.CreateBranch("develop");
fixture.Repository.MakeCommits(5);
fixture.Repository.CreateBranch("Release-2.0.0-Final");
fixture.Repository.Checkout("Release-2.0.0-Final");

        fixture.AssertFullSemver("2.0.0-beta.1+5");
    }
}

[JakeGinnivan]

Fixed in >3.0.0-beta.1 (unreleased)