Version detection fails if "rogue" tags exist

Background / existing situation

The version detection in git_deploy will:
- Use git describe --tags to find the most recent tag name.
- Match this tag name against a regex.

If the most recent tag name does not match, it gives up.

Problem

But what if the most recent tag was just something created for local development, while there is a second most recent tag that does match the regex?

E.g.

{commit id} (HEAD -> 7.x-2.x)
{commit id}
{commit id} (tag: LOCALTEST)
{commit id}
{commit id}
{commit id} (tag: 7.x-2.2)
{commit id}

In this scenario, the version detection would find LOCALTEST and give up, because it does not match the expected format.

Proposed change

First try the describe --tags, as before.
This will work in 99% of cases.
(We could try --match=*.x-*.*, but then we'd have to run it twice to also detect -alpha* versions, and in the end we would still not be 100% safe. This is glob, not regex, unfortunately.)

If this fails, use git log --simplify-by-decoration --format=format:%D.

This produces output like this (from an example project where I had some named local tags)

tag: 7.x-2.x-1511112-53-combined
tag: 7.x-2.x-1511112-50-static-cache-per-git-dir
HEAD, tag: xxxx, origin/HEAD, origin/7.x-2.x, 7.x-2.x
tag: 7.x-2.2
tag: 7.x-2.1
tag: 7.x-2.0

We can use a regex to extract the first tag that matches our expected format, like so:
https://3v4l.org/EoTrg