Regression: order of tags not taken into account

[dcoraboeuf]

Since version 1.7.0, there is the following regression. If a tag 1.0.1 and tag 1.0.2 are created for the release 1.0 branch, the last tag should be taken into account (1.0.2 in this case) before computing the next tag.

However, we now have an order with is lexicographic, and 1.0.1 is taken into account first.

Previous version (1.6) was ordering the tag based on their age.

[dcoraboeuf]

Fixed in 1.7.1